Command Horizontal Shaft
KOHLERENCINES
SERVICE MANUAL
COMMAND 11,12.5,14 HP
lorizontal Crankshaft
Ta a
x
ves
rile. ef dlls.
CONTENTS
SECTION 1. General Information ........... iii a eee seen eee 10000
SECTION 2. Special Tools ............242000 00000 ae ue ua en a ra 00000 ua aa 0000 ue»
SECTION 3. Troubleshooting ........_.eóe._e_rresnsreoascorenmornraonornrreraenra
SECTION 4. Air Cleaner And Intake System .........242220 02100 sua es ana ann m0
SECTION 5. Fuel System And Governor .............2.0 0000000 e een ee es neo uen 0
SECTION 6. Lubrication System ............2200000 000 0e una aa 0e nan 0 en ne ne 0008
SECTION 7. Retractable Starter .............220000 00 0e ea nana na ua een a 0000 u 0
SECTION 8. Electrical System And Components .............. ccna.
SECTION 9. Disassembly ........o_c_eemenarrenvrerecarveronoeoserroreornearnerns
SECTION 10.Internal Components ...............44.200 000 ananas a eau 0e ana ca De
НН
SECTION 11.Reassembly .......eor_coecreororecoaoraoovranennencnmoneanvene ne e
TP-2402
COMMAND 11, 12.5, 14
SECTION 1
GENERAL INFORMATION
FOR YOUR SAFETY
WARNING: For Your Safety!
This symbol points out important safety Warnings and Cautions throughout this
A manual. These Warnings and Cautions should be followed at all times. Failure to
AWARNING
Explosive fuel
can cause fires and severe
bums.
Stop engine before filllng fuel tank.
See Owners Manual.
WARNING: Explosive Fuel!
Gasoline is extremely
A flammable and îts va-
pors can explode if ig-
nited. Store gasoline
only in approved con-
tainers, in well-venti-
fated, unoccupied
buildings, away from
sparks or flames. Do
not fill the fuel tank
while the engine is hot
or running, since
spilfed fuel could ig-
nite if it comes in con-
tact with hot parts or
sparks from ignition.
Do not start the engine
near spilled fuel.
Never use gasoline as
a cleaning agent.
AWARNING
O:
№
Rotating parts
can cause severe injury.
Stay away while engine is in
operation,
See Owners Manual.
WARNING: Rotating Parts!
Keep hands, feet, hair,
and clothing away
from all moving parts
to prevent injury.
Never operate the en-
gine with covers,
shrouds, or guards re-
moved.
follow Warnings and Cautions could result in injury to yourself and others nearby.
AWARNING
Ima
Aaa
|
Hot parts
can cause severe bums.
Do not touch engine while
operating or just after stepping.
See Owner's Manual.
WARNING: Hot Parts!
Engine components
can get extremely hot
from operation. To pre-
vent severe burns, do
not touch these areas
while the engine is run-
ning —or immediately
after it is turned off.
Never operate the en-
gine with heat shields
or guards removed.
1.1
SECTION 1
GENERAL INFORMATION
WARNING:
A
CAUTION:
A
WARNING:
A
WARNING:
A
WARNING:
A
Accidental Starts!
Before servicing the
engine or equipment,
always disconnect the
spark plug lead to pre-
vent the engine from
starting accidentally.
Ground the lead to
prevent sparks that
could cause fires.
Make sure the equip-
ment is in neutral.
Electrical Shock!
Never touch electrical
wires or components
while the engine is
running. They can be
sources of electrical
shock.
Lethal Exhaust
Gases!
Engine exhaust gases
contain poisonous car-
bon monoxide. Carbon
monoxide is odorless,
coforless, and can
cause death if inhaled.
Avoid inhaling exhaust
fumes, and never run
the engine in a closed
building or confined
area.
Overspeed Is
Hazardous!
Do not tamper with the
governor setting. Over-
speed is hazardous
and could cause per-
sonal injury.
Dangerous Acid,
Explosive Gases!
Batteries contain sul-
furic acid. To prevent
acid burns, avoid con-
tact with skin, eyes,
and clothing. Batteries
produce explosive hy-
drogen gas while be-
ing charged. To pre-
vent a fire or explo-
sion, charge batteries
only in well ventilated
areas. Keep sparks,
open flames, and
other sources of igni-
tion away from the
battery at all times.
Keep batteries out of
the reach of children.
Remove all jewelry
when servicing batter-
ies.
Before disconnecting
the negative (-)
ground cable, make
sure all switches are
OFF. If ON, a spark
will occur at the
ground cable terminal
which could cause an
explosion if hydrogen
gas or gasoline va-
pors are present.
WARNING:
WARNING:
A
Flammable Solvents!
Carburetor cleaners
and solvents are ex-
tremely flammable.
Keep sparks, flames,
and other sources of
ignition away from the
area. Follow the
cleaner manufacturer’s
warnings and instruc-
tions on its proper and
safe use. Never use
gasoline as a cleaning
agent.
Spring Under
Tension!
Retractable starters
contain a powerful, flat
wire recoil spring that
is under tension. Do
not remove the center
screw from the starter
until the spring tension
Is released. Removing
the center screw be-
fore releasing spring
tension, or improper
starter disassembly,
can cause the sudden
and potentially danger-
ous release of the
spring.
Always wear safety
goggles when servic-
ing retractable start-
ers —full face protec-
tion is recommended.
To ensure personal
safety and proper start-
er disassembly and
reassembly, follow the
procedures in this sec-
tion carefully.
1.2
SECTION 1
GENERAL INFORMATION
ENGINE IDENTIFICATION NUMBERS
When ordering parts, or in any communication involv-
ing an engine, always give the Model, Specification,
and Serial Numbers of the engine. Include letter suf-
fixes, if there are any.
The engine identification numbers appear on decal (or
decals) affixed to the engine shrouding. See Figure
1-1. The significance of these numbers is shown in
Figure 1-2.
PR TP dE
a ii
E а
identification Decal 8
Figure 1-1. Engine Identification Plate Location.
A. MODEL NO. C H 125 ST
Horizontal Crankshaft
1 —
Command Engine — Version Code
S — Electric Start
Horsepower T= Retractable Start
125 = 12.5hp ST=Electric/Retractable Start
a N
KOHLERENCINE
A
LL
B. SPEC. NO. 1203 MODEL NO. CH125ST a
Engine Model Code _ JTC Variation Of
Code Model Basic Engine REFER TO OWNER'S MANUAL
FOR OPERATION/MAINTENANCE
12 CH12.5 INSTRUCTIONS AND SAFETY
PRECAUTIONS.
BR KOHLER WSCONSIN USA
INA. KOHL
C. SERIAL NO. 2005810334 N 7
Year Manufactured OUT L — Factory Code
20 1990
21 1991
22 1992
23 1993
24 1994
25 1995
SPEC. NO. 1203 ——— B
SERIAL NO. 2005810334 =~] _
Figure 1-2. Significance Of Engine Identification Numbers.
1.3
SECTION 1
GENERAL INFORMATION
OIL RECOMMENDATIONS
Using the proper type and weight of oil in the crank-
case is extremely important. So is checking oil daily
and changing oil regularly. Failure to use the correct
oil, or using dirty oil, causes premature engine wear
and failure.
Oil Type
Use high-quality detergent oil of API (American Pe-
troleum Institute) service class SF, or SG. Select the
viscosity based on the air temperature at the time of
operation as shown in the following table.
Recommended SAE Viscosity Grades
10W-30 10W
?
A À
TEMPER ATURE RANGE EXPECTED REFORE NEXT OIL CHANGE
NOTE: Using other than service class SF or SG oil or
extending oil change intervals longer than rec-
ommended can cause engine damage.
A logo or symbol on oil containers identifies the API
service class and SAE viscosity grade. See Figure
1-3.
Figure 1-3. Oil Container Logo.
Refer to Section 6 — “Lubrication System” for de-
tailed oil check, oil change, and oil filter change
procedures.
FUEL RECOMMENDATIONS
Explosive Fuel!
A vivo Gasoline is extremely flammable and
its vapors can explode if ignited. Store
gasoline only in approved containers,
in well-ventilated, unoccupied build-
ings, away from sparks or flames. Do
not fill the fuel tank while the engine is
hot or running, since spilled fuel
could ignite if it comes in contact with
hot parts or sparks from ignition. Do
not start the engine near spilled fuel.
Never use gasoline as a cleaning
agent.
General Recommendations
Purchase gasoline in small quantities and store in
clean, approved containers. A container with a ca-
pacity of 2 gallons or less with a pouring spout is
recommended. Such a container is easier to handle
and helps eliminate spoilage during refueling.
Do not use gasoline left over from the previous sea-
son, to minimize gum deposits in your fuel system
and to insure easy starting.
Do not add oll to the gasoline.
Do not overfill the fuel tank. Leave room for the
fuel to expand.
Fuel Type
For best results, use only clean, fresh, unleaded
gasoline with a pump sticker octane rating of 87 or
higher. In countries using the Research method, it
should be 80 octane minimum.
Unleaded gasoline is recommended, as it leaves
less combustion chamber deposits. Leaded gaso-
line may be used in areas where unleaded is not
available and exhaust emissions are not regulated.
Be aware however, that the cylinder head will re-
quire more frequent service.
Gasoline/Alcohol blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded
gasoline by volume) is approved as a fuel for Kohler
engines. Other gasoline/alcohol blends are not ap-
proved.
Gasoline/Ether blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blends (up to a maximum of 15% MTBE by
volume) are approved as a fuel for Kohier engines.
Other gasoline/ether biends are not approved.
1.4
SECTION 1
GENERAL INFORMATION
PERIODIC MAINTENANCE
WARNING: Accidental Starts!
Before servicing the engine or equipment, always disconnect the spark plug lead to
prevent the engine from starting accidentally. Ground the lead to prevent sparks that
A
could cause fires.
Maintenance Schedule
These required maintenance procedures should be performed at the frequency stated in the table.
They should also be included as part of any seasonal tune-up.
FREQUENCY MAINTENANCE REQUIRED REFER TO:
Daily Or Fill fuel tank. SECTION 5
Before Check oil level. SECTION 6
Starting Check air cleaner for dirty", loose, or damaged parts. SECTION 4
9 Check air intake and cooling areas, clean as necessary’. SECTION 4
Every Service precieaner element”. SECTION 4
25 Hours
Service air cleaner element‘. SECTION 4
Every Change oil. SECTION 6
100 Hours Check spark plug condition and gap. SECTION 8
Remove cooling shrouds and clean cooling areas’ SECTION 4
Every €
200 Hours Change oil filter. SECTION 6
Annually Or | Service starter motor drive. SECTION 8
Every
500 Hours
i Perform these maintenance procedures more frequently under extremely dusty, dirty conditions.
STORAGE
If the engine will be out of service for two months or
more, use the following storage procedure:
plug, but do not connect the plug lead. Crank the
engine two or three revolutions.
1. Change the oil and oil filter while the engine is still 4. Remove the spark plug and rotate the crankshaft
warm from operation. See “Change Oit And Oil until the piston is at the top of its stroke. Reinstall
Filter” in Section 6. the plug, but do not connect the plug lead.
2. Drain the fuel tank and fuel system (or run the en- 5. Clean the exterior surfaces of the engine.
gine until the fuel tank and fuel system are empty).
6. Store the engine in a ciean, dry place.
3. Remove the spark plug. Add one tablespoon of
engine oil into the spark plug hole. install the
1.5
SECTION 1
GENERAL INFORMATION
[14.78]
E 364.7
[1 4. 36]
23.0
15
[18.17]
ENGINE MOUNTING |
101 а 105.0 SURFACE :
[3.99] [4.13] -
CRANKSHAFT
T WOUNTING HOLE "A" 347.1 - . |
[12.67]
FRONT VIEW
101.0
[3.98] -
; E MOUNTING HOLE TAT
EYLINCER —
€ N
>
AN
Ce
we
[2.34]
Pr
1
449.1
117.68] ;
1 1
430.2
.
[14-947 41.7
113.45]
| PO
L € CRHANKSHAFT
i D 145.0
| ks 165. 1 [5.75] :
: 1 [6.50] PILOT ‘
A - 4
Я | \
No 7716-14 UNC-28 [ INCHI
@ izr.o—" Ny | 21.0 | .83) DEEP
Г ENGINE MOUNTING — | 4 HOLES
[5.00] SURF AGE ; Eo
E 3/8- 16 UNC-ZB INCH |
; 17,0 .&7 | DEEP
[ras 196.8 — i 4 HOLES
[7.75] Ls 16-24 LF -28 1 1NCHI
17.0 [671 DEEP
PTO END °””
RECOIL STARTER SIDE
_— зн CRANKSHAFT —,
MOUNT TNO HOLE =A" — y 175.4 ! $
| 17.69] |
y ! +
я
3/8-16 UNF-2B | INCH] —
22.0 1.871 DEEP
4 HOLES
PAZ 7 y `
Dos — O!L, DRAIN
: 36 - |B MPSF
MOUNTING SURFACE
! .
fr———" 153.0 —
i 6.02
1.68] 1
i
4
|
ig -
x
* \
x. \ — ENGINE MOUNT [NO
§ MOUNTING HOLE "A 3 SURF ACE
“eg CYLINDER
SIDE VIEW - FUEL TA
512,5
——
Гео. 19! Ys CYLINDER
|
348.9 —
[13,74
1
|
|
164.5 |
| [6.44]
9
P.T.0. MOUNTING
SURFACE
MUFFLER ASSEMBLY AND
ARD ARE
MUFTLER 0
OPT | DAL
- E CARANKSHAFT
— OPTIONAL CIL GRAIN
NPSF
NK
185.8 = — ENGINE MOUNT ING
[7.32] к
- —
|- 265.9 “Ng MOUNTING HOLE
110.47] DIMENSIÓN IN|} ARE
CH12.5 B7 BORE Хх 27 STRIKE
= Than
= PLes —
INCH EQUIVALENTE.
SIDE VIEW — AIR CLEANER
127,0
I
| i A ‘ т
| тля о -28 | INCH I 451 ; | — 276 “16 LHC 2A { INCH1
la = DEEP ' = - DEEP
| 2 pcs \ 4 foes
La- 2/8- 18 UNC-ZB | INCH 3 —S/ 10-24 сов INCH }
MOUNTING FACES
4
Figure 1-4. Typical Engine Dimensions.
1.6
SECTION 1
GENERAL INFORMATION
TORQUE
HORSEPOWER
FUEL
Го MJ Ро
en = on
NEWTON -METERS
MJ PJ
+H th
23
ae
El
10
KILOWATTS
(Л
LITERS FER HR.
==
Le
I
un
m
—
LL
2
5
CF
ja
H
MAX. BRAKE
HORSE POWER
E
Li
=
e
EL
Ly
Un
=
5
т
1800 2000 2200 2400 2600 2800 3000 3200 3400 3500
REVOLUTIONS PER MIN.
1.3
1.2
ER HR
50
. 30
REVOLUTIONS PER MIN,
18500 2000 2200 2400 2600 2800 3000 3200 3400 3800
FUEL CONSUMPTION
Figure 1-5. Power, Torque, And Fuel Data.
1.7
SECTION 1
GENERAL INFORMATION
TORQUE INFORMATION, SPECIFICATIONS, AND TOLERANCES
Metric Fastener Torque Recommendations For Standard Applications
Tightening Torque: Nem (Ibf.in) + or - 10%
Property Class Noncritical
IFA FF FF FH FN Fasteners
© +
Size
Ma 1.2 (11) 1.7 (15) 2.9 (26) 4.1 (36) 5.0 (44) 2.0 (18)
M5 2.5 (22) 3.2 (28) 5.8 (51) 8.1 (72) 9.7 (86) 4.0 (35)
M6 4.3 (38) 5.7 (50) 9.9 (88) 14.0 (124) 16.5 (146) 6.8 (60)
M8 10.5 (93) 13.6 (120) 24.4 (216) 33.9 (300) 40.7 (360) 17.0 (150)
Tightening Torque: N-m (Ibf-ft) + or - 10%
Property Class Noncritical
Lm Lm) re EN ram) Fasteners
O
M10 21.7 (16) 27.1 (20) 47.5 (35) 66.4 (49) 81.4 (60) 33.9 (25)
M12 36.6 (27) 47.5 (35) 82.7 (61) 116.6 (86) 139.7 (103) 61.0 (45)
M14 58.3 (43) 76.4 (55) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70)
Oil Drain Plugs Tightening Torque: N-m (English Equiv.) Torque
Size
1/8” NPT
1/4”
3/8”
1/2”
3/4”
X-708-1
Into Cast Iron
17.0 (150 Ibfein)
20.3 (180 Ibfein)
27.4 (20 Ibf-ft)
33.9 (25 Ibf-ft)
27.1/33.9 (20/25 Ibt-ft)
Into Aluminum
4.5 (40 Ibf-in)
11.3 (100 Ibfein)
13.6 (120 Ibfein)
17.6 (13 Ibfeft)
21.7 (16 Ibfeft)
27.1/33.9 (20/25 Ibf-ft)
Conversions
Nm = Ibf-in x 0.113
Nm = Ibf»ft x 1.356
Ibf-in = N.m x 8.85
bfeft = Nem x 0.737
1.8
SECTION 1
GENERAL INFORMATION
SPECIFICATIONS, TOLERANCES, AND SPECIAL TORQUE VALUES!
DESCRIPTION Command 11, 12.5, 14 Hp
General Specifications
Power (@ 3600 rpm, corrected to SAE J1349)
Command 11 ee 8.20 kW (11 hp)
Command 12.5 LL... 220404002444 a 4 a aa aa LL Le A aa a a a a 1 Le a ae 0 0 9.33 kW (12.5 hp)
Command 14.................ersererecesreci caer acera cenenanononer 10.50 kW (14 hp)
Peak Torque
Command 11 ee 27.4 Nem (20.2 Ibf-ft)
Command 12.5 .........eorecesrrreeerreeaaeanerec rie arererermaZZ» 27.8 Nem (20.5 Ibf-ft)
Сотгтпала 14 e eeererecrrand—erererereneoneenen e. 28.9 N.m (21.3 ibf-ft)
Воге ee 87 mm (3.43 in)
fe) EEE 67 mm (2.64 in)
Displacement 102010400444 4444 AA 44e RK RR 398 cm? (24.3 in’)
Compression Ratio oo. eee 8.5:1
Approx. Weight ee 36.3 kg (80 ID)
Approx. Qil CapacHy 20400100 RK 4 a LL a 1144 a a ee 1.9 Е (2.0 U.S. at)
Air Cleaner
Base NUL TOrQUE Le eee 9.9 N.m (88 Ibfein)
Angle Of Operation — Maximum (At Full Oil Level)
Intermittent — AI! Directions .......11011001 1111111 ALL LA LL AL A La LL ALL 1 ALL 35°
Continuous — AÏ! Directions ........121111 11110111 LL LL LL LVL LL 25°
Balance Shaft
End Play (Free) ............... 000000000 iredieacaredanereeno. 0.0575/0.3625 mm (0.0023/0.0143 in)
Running Clearance RR 0.025/0.063 mm (0.0009/0.0025 in)
Bore LD. — New . a LL LL LL LL 11111 Lan 20.000/20.025 mm (0.7874/0.7884 in)
Bore ILD. — Max. Wear Limit... La Lea ae ane 20.038 mm (0.7889 in)
Balance Shaft Bearing Surface O.D. — New ....................... 19.962/19.975 mm (0.7859/0.7864 in)
Balance Shaft Bearing Surface 0.D. — Max. Wear Limit ..................... 19.959 mm (0.7858 in)
Camshaft
End Play (With Shims) 200.0. La a Le a AL 0.076/0.127 mm (0.003/0.005 in)
Running Clearance ...............0 0... 00r0rieeeeareancearedar e 0.025/0.063 mm (0.0010/0.0025 in)
Bore LD. — New enieracarareooaoreaoaneneonean a 20.000/20.025 mm (0.7874/0.7884 in)
Bore LD. — Max. Wear Limit ............ co. i. 20.038 mm (0.7889 in)
Camshaft Bearing Surface O.D. — New ........................... 19.962/19.975 mm (0.7859/0.7864 in)
Camshaft Bearing Surface O.D. —~ Max. Wear Limit . ........................ 19.959 mm (0.7858 in)
1.9
SECTION 1
GENERAL INFORMATION
Carburetor
Preliminary Low Idie Fuel Needle Setting
Command 11 eee 1-1/4 Turn
Command 12.5 000 REEL a ALL AR a a aa era ee 1-1/4 Turn
Command 14 ........... La AL LL ee da a a A A A A a a a a a ea ee ae 1-3/4 Turn
Fuel Bowl Nut Torque .............._ o eer.re: rea 0000.00 eaannanmea 5.1/6.2 Nem (45/55 Ibfein)
Charging
Stator Mounting Screw Torque .............,.0........ ree sreresrererarcerara, 4,0 Nem (35 Ibfein)
Closure Plate
Oil Fler Torque «oe ee eee eee ee ea 5.7/9.0 Nem (50/80 !bfein)
Oil Filter Drain Plug (1/8” NPT) Torque . ......... iia... 7.3/9.0 Nm (65/80 Ibfein)
Closure Plate Fastener Torque .................0.. 000... ea ee aa aa ea ee 24.4 Nem (216 Ibfein)
Oil Sentry Pressure Switch Torque ....... ii 7.9 Nem (70 ibf-in)
Oil Pump Cover Fastener Torque? ..............—....... 0000. 4.0*6.2 Nem (35*55 Ibfein)
Oil Filter Adapter Fastener Torque ..... 0. 0000ee.r ie an. 11.3 Nem (100 Ibfein)
Connecting Rod
Connecting Red Cap Fastener TOrque ..............._..e.0racore criada. 22.6 Nem (200 Ibfein)
Connecting Rod To Crankpin Running Clearance — New .............. 0.030/0.055 mm (0.0012/0.0022 in)
Connecting Rod To Crankpin Running Clearance —
Max. Wear Limif ................... eee 0.07 mm (0.0025 in)
Connecting Rod To Crankpin Side Clearance .................. 2... 0.18/0.41 mm (0.007/0.016 in)
Connecting Rod To Piston Pin Running С1еагапсе .................... 0.015/0.028 mm (0.0006/0.0011 in)
Piston Pin End ED. — New... in 19.015/19.023 mm (0.7486/0.7489 in)
Piston Pin End 1.D. — Max. Wear Limit ............ .. .. a ea 111111011040 19.036 mm (0.7495 in)
Crankcase
Governor Cross ShaftBore ILD. — New ..............—... 2... ... 6.025/6.050 mm (0.2372/0.2382 in)
Governor Cross Shaft Bore ILD. — Max. WearLimit ......................... 6.063 mm (0.2387 in)
Crankshaft
End Play (Free) ea 0.0575/0.4925 mm (0.0023/0.0194 in)
Crankshaft Sleeve Bearing 1.D. — (instalied) New ................... 44.965/45.003 mm (1.7703/1.7718 in)
Crankshaft Sleeve Bearing |.D. — Max. Wearbimit ......_.................. 45.016 mm (1.7723 in)
Crankshaft To Sleeve Bearing Running Clearance — New .............. 0.03/0.09 mm (0.0012/0.0035 in)
Crankshaft Bore (In Oil Pan) To Crankshaft Running
Clearance — New ............. PS 0.03/0.09 mm (0.001 2/0.0035 in)
Flywheel End Main Bearing
(O.D. — New) ee 44.913/44.935 mm (1.7682/1.7691 in)
(O.D. — Max. Wear Limit) .............. a ALL AA La ae aa 2220 44.84 mm (1.765 in)
(Max. Taper) .......... RR нео 0.022 mm (0.0009 in)
(Max. Out Of Round) .......................es.rer:eerereracorerraaoea 0.025 mm {0.0010 in)
1.10
SECTION 1
GENERAL INFORMATION
Closure Plate End Main Bearing Journal
(O.D. — New) eeedareanaererererace о 41.915/41.935 mm (1.6502/1.6510 in)
(O.D. — Max. Wear Limit) ........ L ea A a a ee a ae 10 a 40 41.86 mm (1.648 in)
(Max. TAPE) «oe ea 0.020 mm (0.0008 in)
(Max. Out Of Round) ..... 22... rare raererecerror 0.025 mm (0.0010 in)
Connecting Rod Journal
(O.D. — New) ........ 2... ..eriia es rareceenrerreco 0 38.958/38.970 mm (1.5338/1.5343 in)
(O.D. — Max. Wear Limit) ......... enero 38.94 mm (1.5328 in)
(Max. Taper) RR Le 4 Lea A Le eee ee Le aa 20 0.012 mm (0.0005 in)
(Max. Out Of Round) .............. e. nerariaeaerecor e enero. 0.025 mm (0.0010 in)
Crankshaft T.I.R.
(PTO End, Crank INENGINg) ....... ei 0.15 mm (0.0059 in)
(Entire Crank, IN V-BIOCKS) ... ee 0.10 mm (0.0039 in)
Cylinder Bore
CylinderBore iD. — New ............
Cylinder Bore 1.D. — Max. Wear Limit . . .
Cylinder Bore 1.D. — Max. Qui Of Round
Cylinder Bore [.LD. — Max. Taper ........ i ieee eens
Cylinder Head
Cylinder Head Fastener Torque ........
Max. Out Of Flatness ................
Rocker Pedestal Fastener Torque ......
Electric Starter
Drive Pinion Fastener TOrQUe eee ee ee 15.3 Nem (135 Ibfein)
Drive Pinion To Flywheel Ring GearBacklash ........................ 0.025/1.56 mm (0.001/0.061 in)
Fan/Flywheel
Fan Fastener Torque ..... eee о 9.9 Nem (88 Ibfein)
Flywheel Retaining Screw Torque... oo 111111111110 66.4 Nom (49 |bfeft)
Fuel Pump
Fuel Pump/Cover Fastener Screw Torque? oo... 7.3*9.0 N»m (65*80 Ibfein)
Fuel Tank
Fuel Tank Fastener Torque ............. 2... 2,000.00 aaa ena 7.3 Nom (65 Ibfein)
TE 87.000/87.025 mm (3.4252/3.4262 in)
… 4 & + EA AECE OOOO
4 4 a4 F FF ии = F = FP F F жи ое 4 ¥ F a4 =m a2 = =m =m =m = = = 4 ¥ w =u
а к нок кк ок нод # + + 4 & = = 4 + % 4 F 4 F 4 FF 4 m FB FB = = 5 um
= че = = kh kA = 7 = 4 4 m AAA + FE + a
"=" = = = = § Ww W WT WW OF AF FF # =m =m pg =m kT =m x Fp WE om = =
87.063 mm (3.4277 in)
0.12 mm (0.0047 in)
0.05 mm (0.0020 in)
40.7 Nem (30 lbfeft)
0.076 mm (0.003 in)
9.9 Nem (88 Ibfein)
1.11
SECTION 1
GENERAL INFORMATION
Governor
Governor Cross Shaft To Crankcase Running Ciearance ............... 0.025/0.075 mm (0.0010/0.0030 in)
Governor Cross Shaft O.D. — New ................. 0... eerercee. 5.975/6.000 mm (0.2352/0.2362 in)
Governor Cross Shaft O.D. — Max. Wear Limit .................. a re... ... 5.962 mm (0.2347 in)
Governor Gear Shaft To Governor Gear Running Clearance ............ 0.015/0.140 mm (0.0006/0.0055 in)
Governor Gear Shaft O.D. — New 2... ....0eaaeacenvem. 5.990/6.000 mm (0.2358/0.2362 in)
Governor Gear Shaft O.D. — Max. Wear Limit 2... e... 5.977 mm (0.2353 in)
ignition
Spark Plug Type (Champion Or EQUIV.) «ii ieee eee een RC12YC
Spal PUG Gap «o.oo eee eee 1.02 mm (0.040 in)
Spark Plug Torque ...............e.0r0sr0sar0e, eee LA Ra a a aa 38.0/43.4 N-.m (28/32 Ibf-ft)
Ignition Module Air Gap ...................0. 0... rrecriececareanea. 0.203/0.305 mm (0.008/0.012 in)
ignition Module Fastener Torque ti i i eee 4.0*6.2 Nem (35*55 Ibfein)
Muffler
Muffler Retaining NUS Lo ee 24.4 Nm (216 Ibfein)
Piston, Piston Rings, And Piston Pin
Piston To Piston Pin (Selective Fit) .............. 2... 2... reee. 0.006/0.017 mm (0.0002/0.0007 in)
Piston Pin Bore ID. — New .........221101 100114 a LL 1 aan ee 19.006/19.012 mm (0.7483/0.7485 in)
Piston Pin Bore I.D. — Max. Wear Limit 1.121200 0 0040110040 aa ee a a eee» 19.025 mm (0.7490 in)
Piston Pin O.D. — New ee sees 18.995/19.000 mm (0.7478/0.7480 in)
Piston PIN O.D. — Max. Wear Limit ie eens 18.994 mm (0.74779 in)
Top Compression Ring To Groove Side Clearance ................... 0.040/0.105 mm (0.0016/0.0041 in)
Middle Compression Ring To Groove Side Clearance ................. 0.040/0.072 mm (0.0016/0.0028 in)
Oil Control Ring To Groove Side Clearance iene... 0.551/0.675 mm (0.0217/0.0266 in)
Top And Center Compression Ring End Gap — New Bore ................ 0.3/0.5 mm (0.012/0.020 in)
Top And Center Compression Ring End Gap — Used
Bore (Max) «eee 0.77 mm (0.030 in)
Piston Thrust Face (@D,) To Cylinder Bore Running
Clearance — NEWS |... ee eee a 4» 0.041/0.044 mm (0.0016/0.0017 in)
SECTION 1
GENERAL INFORMATION
Retractable Starter
Center Screw TOQUE «ee ee 7.4/8.5 Nem (65/75 Ibf-in)
Throttie/Choke Controls
Governor Control Lever Fastener Torque «o.oo ii ii ee 9.9 Nm (88 Ibfein)
Speed Control Bracket Assembly Fastener Torquee ............ e... .... 7.3*10.7 Nem (65*95 Ibf-in)
Valve Cover/Rocker Arms
Valve Cover Fastener Torque? 1.120410 00 04401414 e eee a 0 0 a sa a ace ee 7.3*10.7 Nem (65*95 Ibf-in)
Rocker Armi.D. — NeW 111122001101 0 04 aa 0 aa a AL ALL aa a aa a aa 20 15.837/16.127 mm (0.63/0.64 in)
Rocker Arm iD. — Max. Wear Limit... 0404001101 a ea a La aa 0e» 16.13 mm (0.640 in)
Rocker Shaft O.D. — New ieee 15.90/15.85 mm (0.63 in)
Rocker Shaft O.D. — Max. Wear Limit .................0s0ereerer rn ece.. 15.727 mm (0.619 in)
Valves And Valve Lifters
Hydraulic Valve Lifter To Crankcase Running Clearance .............. 0.0124/0.0501 mm (0.0005/0.0020 in)
Intake Valve Stem To Valve Guide Running Clearance ................. 0.038/0.076 mm (0.0015/0.0030 in)
Exhaust Valve Stem To Valve Guide Running Clearance ............... 0.050/0.088 mm (0.0020/0.0035 in)
Intake Valve Guide D. — New a 7.038/7.058 mm (0.2771/0.2779 in)
intake Valve Guide |.D. — Max. Wearbimit ............ ..... ..... ... ...... 7.134 mm (0.2809 in)
Exhaust Valve Guide LD. — New ........... iii. 7.038/7.058 mm (0.2771/0.2779 in)
Exhaust Valve Guide |.D. — Max. Wear Limit ............e—..eseria ries 7.159 mm (0.2819 in)
Valve Guide Reamer Size — SID ............. 020 .ererererecreenaao 200 7.048 mm (0.2775 in)
Valve Guide Reamer Size — 0.25 mm O.8. LK ee 7.298 mm (0.2873 in)
Intake Valve Minimum Lift | aa, 8.96 mm (0.353 in)
Exhaust Valve Minimum Lift ©... ee. 9.14 mm (0.360 in)
Nomina! Valve Seat Angle .... ee cee 45°
NOTES:
1 Values are in Metric units. Values in parenthesis are English equivalents. Lubricate threads with engine oil prior
to assembly.
2 For self-tapping (thread forming) fasteners: the higher torque value is for initial installation into a new cored
hole*the lower torque value is for subsequent installation and installation into tapped holes and weld nuts.
3 Measure 6 mm (0.236 in) above the bottom of the piston skirt at right angles to the piston pin.
1.13
SECTION 1
GENERAL INFORMATION
English Fastener Torque Recommendations For Standard Applications
Tightening Torque: N.m (161411) + or - 20%
Bolts, Screws, Nuts And Fasteners Grade 2 Or 5
Assembled Into Cast Iron Or Steel Fasteners Into
Aluminum
Grade 2 Grade 5 Grade 8
Size
8-32 2.3 (20) 2.8 (25) 2.3 (20)
10-24 3.6 (32) 4.5 (40) 3.6 (32)
10-32 3.6 (32) 4.5 (40) —_— —
1/4-20 7.9 (70) 13.0 (115) 18.7 (165) 7.9 (70)
1/4-28 9.6 (85) 15.8 (140) 22.6 (200) —_—
5/16-18 17.0 (150) 28.3 (250) 39.6 (350) 17.0 (150)
5/16-24 18.7 (165) 30.5 (270) — —
3/8-16 29.4 (260) —
3/8-24 33.9 (300)
Tightening Torque N-m (Ibf-ft) + or - 20%
Size
5/16-24 40.7 (30)
3/8-16 47.5 (35) 67.8 (50)
3/8-24 54.2 (40) 81.4 (60)
7/16-14 47.5 (35) 74.6 (55) 108.5 (80)
7/16-20 61.0 (45) 101.7 (75) 142.4 (105)
1/2-13 67.8 (50) 108.5 (80) 155.9 (115)
1/2-20 94.9 (70) 142.4 (105) 223.7 (165)
9/16-12 101.7 (75) 169.5 (125) 237.3 (175)
9/16-18 135.6 (100) 223.7 (165) 311.9 (230)
5/8-11 149.2 (110) 244 1 (180) 352.6 (260)
5/8-18 189.8 (140) 311.9 (230) 447.5 (330)
3/4-10 199.3 (150) 332.2 (245) 474.6 (350)
3/4-16 271.2 (200) 440.7 (325) 637.3 (470)
COMMAND 11, 12.5, 14
SECTION 2
SPECIAL TOOLS
SPECIAL SERVICE TOOL KITS shaft pin and camshaft pin cup plug installation, MV
oil seal installation tools, and a tool board.
These quality tools are designed to help you perform
specific disassembly, repair, and reassembly proce- COMMAND Tool Kit No. KO-3213 — This kit is de-
dures. By using tools designed for the job, you can signed for the current Kohler Engine Service Dealer
service engines easier, faster, and safer! In addition, already having the KO-3211-A basic tool kit. This kit
you'll increase your service capabilities and customer includes ail additional tools necessary to service cur-
satisfaction by decreasing engine down time. rent Command series engines.
COMMAND Tool Kit No. KO-3214 — This kit is for
the new Kohler Dealer servicing the Command series
engines only.
Tool Kit No. KO-3211-A — This basic tool kit in-
cludes tools necessary to service Kohler K-Series and
Magnum engines. It includes the tools originally sold
as kit NU-3211 and the new tools kit no. KO-3212. COMMAND Too! Kit No. KO-3215 — This kit is for
the new Kohler Dealer servicing the Command 77,
Tool Kit No. KO-3212 — This kit updates original tool 12.5, 14 models only.
kit No. NU-3211 to include all new tools released in
1886 and 1987. Specifically, the kit includes fixed jet To avoid tool duplication, and to ensure you have all
carburetor welch plug removal and installation, cam- necessary tools, refer to the following table:
IF YOU ARE CURRENTLY SERVICING ORDER KIT NO.
KO-3211-A | KO-3212 KO-3213 KO-3214 | KO-3215
New/Existing Kohler Dealer “No Tools” К, М, & С X X
Existing Kohler Dealer With NU-3211 Kit K&M X
Existing Kohler Dealer With NU-3211 Kit К, М, & С X X
Existing Kohler Dealer With KO-3211-A Kit К, М, & С X
Existing Kohler Dealer Command Only С X
Existing Kohler Dealer Command 11,
12.5, 14 Only С X
K = K-Series Engines
M = Magnum Engines
C = Command Engines
KO-3211-A = Standard Tool Kit For K-Series And Magnum Engines (Includes Kits NU-3211 And K0-3212)
KO-3212 = Add On Kit For NU-3211 (Kit KO-3212 + Kit NU-3211 = Kit K0-3211-A)
KO-3213 = Add On Kit For Command Series Engines (To Be Used With Kit KO-3211-A)
KO-3214 = Command Dealer Tool Kit ”
KO-3215 = Command 11, 12.5, 14 Dealer Tool Kit
2.1
SECTION 2
SPECIAL TOOLS
Kit KO-3213 Includes:
Tool No. Description Application Hustration
KO-1026 | REAMER Used to ream valve guides.
(Oversize Valve
Guide)
KO-1027 | OIL SEAL Used to instal! oil seais to the proper
INSTALLER depth. Use with KO-1036 handle.
(Flywheel, PTO)
KO-1028 | CRANKSHAFT Used to install main bearing. Use
BEARING with NU-4747 handle.
INSTALLER
KO-1029 | CRANKSHAFT Used to remove main bearing. Use
BEARING with NU-4747 handie.
REMOVER
KO-1030 | GOVERNOR SHAFT | Used to install governor shaft seal.
SEAL INSTALLER
KO-1031 | CAMSHAFT Used to check camshaft endpiay. (All
ENDPLAY PLATE necessary hardware is included.)
KO-1033 | REAMER Used to ream valve guides — CHS.
(Oversize Valve
Guide)
2.2
SECTION 2
SPECIAL TOOLS
Tool No. Description Application Hustration
KO-1034 | OIL SEAL Used to install oil seals to the proper
INSTALLER depth— CH5. Use with KO-1036 han-
(Flywheel, PTO) dle.
KO-1035 | CAMSHAFT PTO Used to install the camshaft PTO oil
OIL SEAL seal to the proper depth— CHS. Use
INSTALLER with KO-1036 handie.
KO-1036 | DRIVING HANDLE | Used with oil seal installers.
dl
KO-1037 | SEAL PROTECTOR | Used on crankshaft when installing
SLEEVE oil seals.
208665 HEX CAP SCREW Used with flywheel puller kit
(NU-3226) — All. (M8x1.25x70 mm)
10257 FLAT WASHER Used with flywheel puller kit — All. NOT ILLUSTRATED
KO-1039 | SILO PACK, Used with KO-3213 kit.
HOOKS, SCREWS
2.3
SECTION 2
SPECIAL TOOLS
Kit KO-3214 Includes All Of The Above Tools Plus The Following:
Tool No. Description Application illustration
NU-4747 | HANDLE Used to install and remove bearings.
1
== —-
NU-10357 | FLYWHEEL STRAP | Used to hold flywheel.
WRENCH (For replacement strap, order part no.
305085.) ZZ)
NU-12018 | BEARING Used to install main bearings — CHS.
INSTALLER Use with NU-4747 handle.
NU-12021 | SEAL PROTECTOR | Used on crankshaft when installing
SLEEVE oil seals —CH5.
NU-3226 | FLYWHEEL Used to remove flywheel.
PULLER KIT (All hardware included.)
KO-1038 |! TOOL BOARD Used with KO-3214 kit.
KO-1040 | SILO PACK,
HOOKS, SCREWS NOT ILLUSTRATED
2.4
SECTION 2
SPECIAL TOOLS
Kit No. KO-3214 Tool Usage Chart
Number Description C5 CV and CH 11,12.5, 14
KO-1026 Reamer, Oversized Valve Guide X Е
KO-1027 Oil Seal Installer (Flywheel) X
KO-1028 Crankshaft Bearing Installer X
KO-1029 Crankshaft Bearing Remover X
KO-1030 Governor Shaft Seal installer X
KO-1031 Camshaft Endplay Plate X
KO-1033 Reamer, Oversized Valve Guide X
KO-1034 Oil Seal Instalier (Flywheel, PTO) X
KO-1035 Camshaft PTO Qil Seal Installer X
KO-1036 Driving Handle X X
KO-1037 Seal Protector Sleeve X
208665 Hex Cap Screw (M8x1.25x70 mm) X X
10257 Flat Washers X X
208562 Hex Cap Screws (M8x1.25x20 mm) X
KO-1039 SHo Pack, Hooks, And Screws (KO-3213) X X
NU-3226 Fiywheel Puller Kit X X
NU-4747 Handle X X
NU-10357 Flywheel Strap Wrench X X
NU-12018 Bearing Installer X
NU-12021 Seal Protector Sleeve X
KO-1038 Tool Board X X
KO-1040 Silo Pack, Hooks, And Screws (KO-3214) X X
Service tool kits can be ordered complete or the tools
can be ordered individually. Contact your Kohler Dis-
tributor for price and availability.
2.5
SECTION 2
SPECIAL TOOLS
ENGINE ANALYSIS KIT NO. KO 25 800 01
Digital Tachometer
Digital Engine Analyzer
Thermocouples
Digital Voltmeter
es
Rr
Digital Thermometer
Slack Tube Manometer
Carrying Case
Figure 2-1. Engine Analysis Kit — 25 800 01
The Kohler Engine Analysis Kit contains a selection of
instruments that will enable you to measure critical
items that relate to engine performance. You will find
many uses for these instruments — from basic crank-
case vacuum checks to sopisticated application tests.
Qty. Description
Digital Voltmeter
Digital Tachometer
Digital Thermometer
Digitai Engine Analyzer
Slack Tube Manometer
8 Ft. Lead With Plug
14mm Spark Plug
Thermocouple
Head Bolt Thermocouple
Oil Sump Thermocouple
1/4” x 1/8” Bushing
3/8” x 1/8” Bushing
1/2” x 1/8” Bushing
3/4” x 1/8” Bushing
Tube With Fittings
Carrying Case
Plain Thermocouple
Ca) = = = = = À
Ca) —À = = = к A A Y
The Engine Analysis Kit Includes:
Part No.
KO 25 800 02
KO 25 800 03
KO 25 800 04
KO 25 800 05
KO 25 800 06
KO 25 800 07
KO 25 800 08
KO 25 800 09
KO 25 800 10
KO 25 800 11
KO 25 800 12
KO 25 800 13
KO 25 800 14
KO 25 800 15
KO 25 800 16
KO 25 800 17
The voltmeter, tachometer, and engine analyzer feature
electronic circuitry and digital readouts. Guidelines for
using the instruments and testing are included,
2.6
SECTION 2
SPECIAL TOOLS
Using the instruments in the kit you will be able to: 4, Measure voltage.
1. Measure the temperatures of the:
a. spark plug base gasket/cylinder head bolt,
b. oil sump, and
c. air into flywheel and carburetor.
5. Measure charging system current.
6. Measure electric starter current (Amp) draw.
2. Measure engine speed (rpm). The Engine Analysis Kit can be ordered complete as
shown, or the instruments can be ordered individually.
3. Measure crankcase vacuum and exhaust system Contact your Kohler Distributor for price and availabil-
back pressure. ity.
Spring Clip | Additional Components For
BR Twin Cylinder Engines
—
Spark Plug
; | 1/2" LD. Fuel Line
| 1-1/4” Long
18 GA. Wire = —"
Remove Ground |
Electrode o
— Spark Plug
#
ST 0.025” Gap
! |
Spring Clip !
Alligator Clip py
1/2” 1.D. Fuel Line__—"
1-1/4" Long
Figure 2-2. Electronic Magneto Ignition System Tester.
IGNITION SYSTEM TESTER
These engines are equipped with a dependable elec-
tronic magneto ignition system. A simple tester can be
used to determine if the ignition module is functioning
properly. See Figure 2-2.
2.7
SECTION 2
SPECIAL TOOLS
Tester Construction
1. Obtain a new RJ-8 or RCJ-8 spark plug.
2. Remove the ground electrode from the spark plug.
This gives a spark gap of approx. 3.3 mm (0.13
in}. This large gap simulates the spark required
under actual engine conditions.
3. Make a lead assembly using a large spring clip,
an alligator clip, and 18 gauge wire.
4. Cut 2 32 mm (1-1/4 in) length of 13 mm (1/2 in)
1.D. fuel line. Slide it onto the threads of the test
plug. The fuel line shades the firing tip to make
the spark more visible.
Using The Tester
Follow the instructions given in Section 8 — “Electrical
System And Components.”
ELECTRIC STARTER BRUSH HOLDER
TOOL
The electric starter motor brush holder will make the
installation of the commutator end cap to the starter
frame much easier. The brush holder tool can easily
be made from thin sheet metal. See Figure 2-3.
Sheet Metal
Brush Holder Tool
1 i/g"
Brush Holder Tool Installed
Over Brushes And End Cap
Figure 2-3. Brush Holder Tool.
RTV SILICONE SEALANT
RTV silicone sealant is used as a gasket between the
crankcase and oil pan and between the rocker cover
and cylinder head. General Electric Silmate™ type
RTV-1473, or RTV-108 (or equivalent) silicone
sealant is recommended.
Silicone Sealant Dispenser
Figure 2-4. Silicone Sealant Dispenser.
An easy-to-use silicone sealant dispenser, part no.
52 597 01, is available. This dispenser contains
142cc (4.8 fl.oz.) of RTV-108. See Figure 2-4.
This dispenser also features easy-to-use One Touch®
control, precise dispensing of the correct bead and
amount of sealant, and a 1-year shelf life for an un-
opened can — 6 months shelf life after can has been
opened.
To order, contact your source of supply.
2.8
COMMAND 11, 12.5, 14
SECTION 3
TROUBLESHOOTING
TROUBLESHOOTING GUIDE
When troubles occur, be sure to check the simple
causes which, at first, may seem toc obvious to be
considered. For example, a starting problem could be
caused by an empty fuel tank.
Some common causes of engine troubles are listed
below. Use these to locate the causing factors.
Engine Cranks But Will Not Start
1. Empty fuel tank
. Fuel shutoff valve closed
. Dirt or water in the fuel system
. Clogged fuel line
. Spark plug lead disconnected
. Keyswitch or kill switch in “off” position
. Faulty spark plug
. Faulty ignition module
CAS ©) сл + © N
Engine Starts But Does Not Keep Running
1. Restricted fuel tank vent
2. Dirt or water in the fuel system
3. Faulty choke or throttle controls/cables
4. Loose wires or connections that short the
Kill terminal of ignition module to ground
. Faulty cylinder head gasket
. Fauity fuel pump
7. Faulty carburetor
Oo OT
Engine Starts Hard
4
60 SO SQ N
. Hydrostatic transmission not in neutral/PTO
drive is engaged
. Dirt or water in the fuel system
. Clogged fuel line
. Loose or faulty wires or connections
. Faulty choke or throttle controls/cables
. Faulty spark plug
. Low compression
. Faulty ACR mechanism
Engine Wilt Not Crank
1
60 AJ O9 O7 4 OU о
. Hydrostatic transmission not in neutral/PTO
drive is engaged
. Battery is discharged
. Safety interlock switch is engaged
. Loose or faulty wires or connections
. Faulty keyswitch or ignition switch
. Faulty electric starter/starter solenoid
. Retractable starter not engaging in drive cup
. Seized internal engine components
Engine Runs But Misses
1
X
. Dirt or water in the fuel system
2.
3.
Spark plug lead disconnected
| cose wires or connections that intermittently
short the kill terminal of ignition module to
ground
. Engine overheated
. Faulty ignition module
3.1
SECTION 3
TROUBLESHOOTING
Engine Will Not idle
1. Restricted fuel tank vent
. Dirt or water in the fuel system
. Faulty spark plug
. Idle fuel adjusting needle improperly set
. Idle speed adjusting screw improperly set
. Low compression
So a. wr
Engine Overheats
1. Air intake/grass screen, cooling fins, or
cooling shrouds clogged
2. Excessive engine load
3. Low crankcase oil level
4. High crankcase oll level
Engine Knocks
1. Excessive engine load
2. Low crankcase oil level
3. Old/improper fuel
4. internal wear or damage
Engine Loses Power
1. Low crankcase oll level
. High crankcase oil level
. Dirty air cleaner element
. Dirt or water in the fuel system
. Excessive engine load
. Engine overheated
. Faulty spark plug
. Low compression
O ~~ Ob WN
Engine Uses Excessive Amount Of Oil
1. Incorrect oil viscosity/type
2. Clogged or improperly assembled breather
3. Worn or broken piston rings
4. Worn cylinder bore
5. Wom valve stems/valve guides
EXTERNAL ENGINE INSPECTION
Before cieaning or disassembling the engine, make a
thorough inspection of its external appearance and
condition. This inspection can give clues to what
might be found inside the engine (and the cause)
when it is disassembled.
LI Check for buildup of dirt and debris on the crank-
case, cooling fins, grass screen and other external
surfaces. Dirt or debris on these areas are causes
of overheating.
[1 Check for obvious fuel and oil leaks, and dam-
aged components. Excessive oil leakage can in-
dicate a clogged or improperly assembled
breather, wom or damaged seals and gaskets, or
loose or improperly torqued fasteners.
[3 Check the air cleaner cover and base for damage
or indications of improper fit and seal.
[1 Check the air cleaner element. Look for holes,
tears, cracked or damaged sealing surfaces, or
other damage that could allow unfiltered air into
the engine. Also note if the element is dirty or
clogged. These could indicate that the engine has
been underserviced.
[7] Check the carburetor throat for dirt, Dirt in the
throat is further indication that the air cleaner is not
functioning properly.
1 Check the oil level. Note if the oi! level is within
the operating range on the dipstick, or if it is low
or overfilied.
D) Check the condition of the oil. Drain the oil into a
container —the oil should flow freely. Check for
metal chips and other foreign particles.
Sludge is a natural by-product of combustion; a
small accumulation is normal. Excessive siudge
formation could indicate the oil has not been
changed at the recommended intervals, the incor-
rect type or weight of oil was used, overrich car-
buretion, and weak ignition, to name a few.
NOTE: It is good practice to drain oil at a loca-
tion away from the workbench. Be sure to
allow ample time for complete drainage.
CLEANING THE ENGINE
After inspecting the external condition of the engine,
clean the engine thoroughly before disassembling it.
Also clean individual components as the engine is
disassembled. Only clean parts can be accurately
inspected and gauged for wear or damage. There are
many commercially available cleaners that will quickly
remove grease, oil, and grime from engine parts.
When such a cleaner is used, follow the manufactur-
er's instructions and safety precautions carefully.
Make sure all traces of the cleaner are removed be-
fore the engine is reassembled and placed into opera-
3.2
SECTION 3
TROUBLESHOOTING
tion. Even small amounts of these cleaners can
quickly break down the lubricating properties of en-
gine cil.
BASIC ENGINE TESTS
Crankcase Vacuum Test
A partial vacuum should be present in the crankcase
when the engine is operating at normal temperatures.
Pressure in the crankcase (normally caused by a
clogged or improperly assembled breather) can cause
oil to be forced out at oil seals, gaskets, or other
available spots.
Crankcase vacuum is best measured with a water
manometer. The manometer included in the Kohler
Engine Analysis Kit is recommended. Refer to Section
2 — “Epecial Tools” for more information.
Test the crankcase vacuum with the manometer as
follows:
1. Insert the stopper/hose into the oil fill hole. Leave
the other vent hose of manometer open to aimos-
phere.
Make sure the shutoff clamp Is closed.
2. Start the engine and run at no-load high idle
speed (3200 to 3750 rpm).
3. Open the clamp and note the water level in the
tube.
The level in the engine side should be a minimum
of 10.2 cm (4 in) above the level in the open side.
If the level in the engine side is the same as the
open side (no vacuum), or the level in the engine
side is lower than the levei in the open side (pres-
sure), check for the conditions in the table below.
4. Close the shutoff clamp before stopping the en-
gine.
Compression Test
These engines are equipped with an automatic com-
pression release (ACR) mechanism. Because of the
ACR mechanism, it is difficult to obtain an accurate
compression reading.
To check the condition of the combustion chamber
and related mechanisms, physical inspection and a
crankcase vacuum test are recommended.
NO CRANKCASE VACUUM/PRESSURE IN CRANKCASE
Possible Cause
Solution
1. Crankcase breather clogged or inoperative.
2. Seals and/or gaskets leaking. Loose or improperly
torqued fasteners.
3. Piston blowby or leaky valves. {Confirm by inspect-
ing components.)
4. Restricted exhaust.
. Disassemble breather, clean parts thoroughly, reas-
semble, and recheck pressure.
. Replace all worn or damaged seals and gaskets.
Make sure all fasteners are tightened securely. Use
appropriate torgue values and sequences when nec-
essary.
. Recondition piston, rings, cylinder bore, valves,
and valve guides.
. Repair/replace restricted muffler/exhaust system.
3.3
SECTION 3
TROUBLESHOOTING
3.4
COMMAND 12.5
SECTION 4
AIR CLEANER & AIR INTAKE SYSTEM
AIR CLEANER Air Cleaner Service
Check the air cleaner daily or before starting the en-
gine. Check for and correct heavy buildup of dirt and
debris, and ioose or damaged components.
These engines are equipped with a replaceable, high-
density paper air cleaner element. Some engines are
also equipped with an oiled-foam precleaner which
surrounds the paper element. See Figures 4-1 and NOTE: Operating the engine with loose or damaged
4-2. air cleaner components could allow unfiltered
air into the engine causing premature wear
and failure.
Service Precleaner
If so equipped, wash and reoil the precieaner every
25 hours of operation (more often under extremely
dusty or dirty conditions).
1. Remove the precleaner from the paper element.
2. Wash the precieaner in warm water with detergent.
Rinse the precteaner thoroughly untit all traces of
detergent are eliminated. Squeeze out excess
water (do not wring). Allow the precieaner to air-
dry.
Figure 4-1. Air Cleaner Housing Components. 3. Saturate the precieaner with new engine oil.
Squeeze out all excess oil.
4. Reinstall the precleaner over the paper element.
Air Cleaner Base
Element Cover 5. Reinstall air cleaner cover, and air cleaner cover
retaining knob. Make sure the knob is tightened
DD securely.
9; Paper Element Service Paper Element
— E” AD i my | Every 100 hours of operation (more often under ex-
«a A ‚ tremely dusty or dirty conditions), check the paper
yo a element. Replace the element as necessary.
Element Cover Wing Nut [uy Foam Precleaner 1. Remove the precleaner (if so equipped) from the
No -— aper element.
2. Remove the wing nut, washer, element cover, and
Figure 4-2. Air Cleaner Elements. air cleaner element.
4.1
SECTION 4
AIR CLEANER & AIR INTAKE SYSTEM
3. Do not wash the paper element or use pressurized
air, as this will damage the element. Replace a
dirty, bent, or damaged element with a genuine Koh-
ler element. Handle new elements carefully; do not
use of the sealing surfaces are bent or damaged.
4. Reinstall the paper element, element cover, washer,
wing nut, precleaner, air cleaner cover, and air
cleaner cover retaining knob. Make sure the knob is
tightened securely.
Inspect Air Cleaner Components
Whenever the air cleaner cover is removed, or the pa-
per element or precieaner are serviced, check the fol-
lowing areas/components:
Covered Air Cleaner Element — Inspect the rubber
grommet in the hole of the air cleaner element cover.
Replace the grommet if it is wom or damaged.
Air Cleaner Base — Make sure the base is secured
and not cracked or damaged. Since the air cleaner
base and carburetor are secured to the intake port
with common hardware, it is extremely important that
the nuts securing these components are tight at all
times.
Breather Tube — Make sure the tube is installed to
both the air cleaner base and valve cover.
NOTE: Damaged, wom, or loose air cleaner compo-
nents can allow unfiltered air into the engine
causing premature wear and failure. Tighten or
replace all loose or damaged components.
Disassembly
The following procedure is for complete disassembly
of all air cleaner components.
1. Remove the air cleaner cover retaining knob and
air cleaner cover.
2. If so equipped, remove the precleaner from paper
element.
3. Remove the wing nut, washer, element cover, and
air cleaner element.
4. Disconnect the breather hose from the valve cov-
er.
5. Remove the air cleaner base mounting nuts, air
cleaner base, and gasket.
B. If necessary, remove the self-tapping screws and
elbow from air cleaner base.
Reassembly
The following procedure is for compiete assembly of
all air cleaner components.
1. Install the elbow and self-tapping screws to air
cleaner base.
2. Install the gasket, air cleaner base, and base
mounting nuts, Torque the nuts to 9.9 N.m (88
ibf-in).
3. Connect the breather hose to the air cleaner base
(and valve cover). Secure with hose clamps.
4. If necessary, install the grommet into the cover of
air cleaner element. Install the air cleaner element,
element cover, washer, and wing nut.
5. If so equipped, install the precteaner (washed and
oiled) over the paper element.
6. Install the air cleaner cover and air cleaner cover
retaining knob. Tighten the knob securely.
AIR INTAKE/COOLING SYSTEM
Clean Air Intake/Cooling Areas
To ensure proper cooling, make sure the grass screen,
cooling fins, and other external surfaces of the engine
are kept clean at all times.
Every 100 hours of operation {more often under ex-
tremely dusty, dirty conditions), remove the blower
housing and other cooling shrouds. Clean the cooling
fins and external surfaces as necessary. Make sure
the cooling shrouds are reinstalled.
NOTE: Operating the engine with a blocked grass
screen, dirty or plugged cooling fins, and/or
cooling shrouds removed, will cause engine
damage due to overheating.
4.2
COMMAND 11, 12.5, 14
SECTION 5
FUEL SYSTEM AND GOVERNOR
Explosive Fuel! Gasoline/Alcohol blends
A vrs Gasoline is extremely flammable and
its vapors can explode if ignited. Be-
fore servicing the fuel system, make
sure there are no sparks, open flames,
— or other sources of ignition nearby as
Gasoho! (up to 10% ethyl alcohol, 90% unleaded
gasoline by volume) is approved as a fuel for Kohler
engines. Other gasoline/alcohol blends are not ap-
proved.
these can ignite gasoline vapors. Dis-
connect and ground the spark plug
fead to prevent the possibility of sparks
Gasoline/Ether blends
from the ignition system. Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blends (up to a maximum of 15% MTBE by
FUEL RECOMMENDATIONS volume) are approved as a fuel for Kohler engines.
General Recommendations Other gasoline/ether blends are not approved.
Purchase gasoline in small quantities and store in
clean, approved containers. A container with a ca- FUEL SYSTEM
pacity of 2 gallons or less with. a pouring spout is
recommended. Such a container is easier to handle
and helps eliminate spoilage during refueling.
The typical fuel system and related components in-
clude the fuel tank, in-line fuel filter, fuel pump, carbu-
retor, and interconnecting fuel lines.
Do not use gasoline left over from the previous sea-
son, to minimize gum deposits in your fuel system
and to insure easy starting. Operation
Do not add oil to the gasoline. The fuel from the tank is moved through the in-line fil-
ter and fuel lines by the fuel pump. On engines not
equipped with a fuel pump, the fuel tank outiet 1s lo-
cated above the carburetor inlet; gravity moves the
Fuel Type fuel.
Do not overfill the fuel tank. Leave room for the
fuel to expand.
For best results, use only clean, fresh, unleaded Fuel then enters the carburetor float bow! and is
gasoline with a pump sticker octane rating of 87 or moved into the carburetor body. There, the fuel is
higher. In countries using the Research method, It mixed with air. This fuel-air mixture is then burned in
should be 90 octane minimum. the engine combustion chamber.
Unleaded gasoline is recommended, as it leaves
less combustion chamber deposits. Leaded gaso- Troubleshooting
line may be used in areas where unleaded is not
available and exhaust emissions are not regulated.
Be aware however, that the cylinder head will re-
quire more frequent service.
Use the following procedure to check if fuel is reach-
ing the combustion chamber.
5.1
SECTION 5
FUEL SYSTEM AND GOVERNOR
Test
Conclusion
1. Check for the following:
A. Make sure the fuel tank contains fuel,
B. Make sure the vent in fuel tank in open.
C. Make sure the fuel shutoff valve is open.
2. Check for fuel in the combustion chamber.
A. Disconnect the spark plug lead.
B. Close the choke on the carburetor.
C. Crank the engine several times.
D. Remove the spark plug and check for fuel at the tip,
2. If there is fuel at the tip of the spark plug, fuel is reaching the
combustion chamber.
If there is no fuel at the tip of the spark plug, check for fuel flow
from the fuel tank. (Test 3.)
3. Check for fuel flow from the tank to the fuel pump.
A. Remove the fuel line from the inlet fitting of fuel pump.
B. Hold the line below the bottom of the tank. Open the
shutoff valve (if so equipped) and observe flow.
3. If fuel does flow from the line, check for faulty fuel pump.
(Test 4.)
If fuel does not flow from the line, check for clogged fuel tank
vent, fuel pickup screen, shutoff valve, and fuel lines.
4. Check the operation of fuel pump.
A. Remove the fuel line from the inlet fitting of carburetor.
8. Crank the engine several times and observe flow.
4. If fuel does flow from the line, check for faulty carburetor.
(Refer to the “Carburetor” portions of this Section.)
If fuel does not flow from the line, check for clogged fuel line.
if the fuel line is unobstructed, the fuel pump is faulty and must
be replaced.
FUEL FILTER
Some engines are equipped with an in-line fuel filter.
Visually inspect the filter periodically, and replace
when dirty with a genuine Kohler filter.
FUEL PUMP
Some engines are equipped with an optional me-
chanically operated fuel pump. On applications using
a gravity feed fuel system, the fuel pump mounting
pad is covered with a metal plate.
The fuel pump body is constructed of nylon. The nylon
body insulates the fuel from the engine crankcase.
This prevents the fuel from vaporizing inside the
pump.
Operation
The mechanical pump is operated by a lever which
rides on the engine camshaft. The lever transmits a
pumping action to the diaphragm inside the pump
body. On the downward stroke of the diaphragm, fuel
is drawn in through the inlet check valve. On the up-
ward stroke of the diaphragm, fue! is forced out
through the outlet check valve. See Figure 5-1.
5.2
SECTION 5
FUEL SYSTEM AND GOVERNOR
Outlet Camshaft
Check
Valve
Lever
Inlet
Diaphragm Check Valve
Figure 5-1. Cutaway — Typical Fuel Pump.
Removal
1. Disconnect the fuel lines from the inlet and outlet
fittings of pump.
2. Remove the hex. flange screws, fuel pump, and
gasket.
3. If necessary, remove the fittings from the pump
body.
Repair
Nylon-bodied fuel pumps are not serviceable and
must be replaced when faulty. Replacement pumps
are available in kits that include the pump and mount-
ing gasket.
Installation
1. Fittings — Apply a small amount of Permatex®
Aviation Perm-A-Gasket (or equivalent) gasoline
resistant thread sealant to the threads of fittings.
Turn the fittings into the pump 6 full turns; con-
tinue turning the fittings in the same direction until
the desired position is reached.
2. Install new gasket, fuel pump, and hex. flange
SCrews,
NOTE: Make sure the fuel pump lever is posi-
tioned to the RIGHT of the camshaft
(when looking at fuel pump mounting
pad). Damage to the fuel pump, and sub-
sequent severe engine damage could re-
sult if the lever is positioned to the left of
the camshaft.
Torque the hex. flange screws as follows:
First Time Installation On A New Short Block —
9.0 N-m (80 Ibf-in)
— Al Reinstallations — 7.3 N.m (65 Ibf-in).
3. Connect the fuel lines to the inlet and outlet fit-
tings.
CARBURETOR
These engines are equipped with an adjustable main
jet carburetor. This subsection covers the
troubleshooting, idle adjustment, and service proce-
dures for the carburetor.
Explosive Fuel!
A warnıng Gasoline may be present in the carbu-
retor and fuel system. Gasoline is ex-
tremely flammable and its vapors can
explode if ignited. Keep sparks, open
—l= flames, and other sources of ignition
away from the engine. Disconnect and
ground the spark plug lead to prevent
the possibility of sparks from the igni-
tion system.
5.3
SECTION 5
FUEL SYSTEM AND GOVERNOR
Troubleshooting pump for restrictions or faulty components as nec-
essary.
If engine troubles are experienced that appear to be
fuel system related, check the following areas before [J Make sure the air cleaner base and carburetor is
adjusting or disassembling the carburetor.
securely fastened to the engine using gaskets in
good condition.
[1 Make sure the fuel tank is filled with clean, fresh Make sure the air cleaner element is clean and all
gasoline.
[1 Make sure the fuel tank cap vent is not blocked
and that it is operating properly.
air cleaner components are fastened securely.
[J Make sure the ignition system, govemor system,
exhaust system, and throttle and choke controls
are operating properly.
[J Make sure fuel is reaching the carburetor. This If the engine is hard-starting or runs roughly or stall at
includes checking the fuel shut-off valve, fuel tank low idle speed, it may be necessary to adjust or ser-
filter screen, in-line fuel filter, fuel lines, and fuel vice the carburetor.
Condition Possible Cause/Probable Remedy
1. Engine starts hard, or runs roughly or
stalls at idle speed.
. Low idie fuel mixture or speed are improperly adjusted. Adjust the low idle speed screw,
then adjust the low idle fuel needle.
2. Engine runs rich. {Indicated by black,
sooty exhaust smoke, misfiring, loss of
speed and power, governor hunting, or
excessive throttle opening.)
2a.
т
Choke partially closed during operation. Check the choke lever/linkage to ensure choke
is operating properiy.
. Low idle fuel mixture is improperly adjusted. Adjust low idle fuel needle.
. Float level is set too high. With fuel bowl removed and carburetor inverted, the exposed
surface of float must be parallel with the bow! gasket surface of the carburetor body.
. Dirt under the fuel inlet needle. Remove needle; clean needle and seat and blow with
compressed air.
. Bowl vent or air bleeds plugged. Remove fuel bowl, low idle fuel adjusting needle, and
welch plugs. Clean vent, ports, and air bleeds. Blow out all passages with compressed
air.
Fuel bowl gasket leaks. Remove fuel bowl and replace gasket.
. Leaky, cracked, or damaged float. Submerge fioat to check for leaks.
3. Engine runs lean. {Indicated by misfir-
ing, loss of speed and power, governor
hunting, or excessive throttle opening.)
3a.
Low idle fuel mixture is improperly adjusted. Adjust low idle fuel needie.
. Float level is set too low. With fuel bowl removed and carburetor inverted, the exposed
surface of float must be parallel with the bowl gasket surface of the carburetor body.
. Idle holes plugged; dirt in fuel delivery channels. Remove fuel bowl, low idle fuel adjust-
ing needle, and welch plugs. Clean main fuel jet and all passages; blow out with com-
nressed air.
4. Fuel leaks from carburetor.
da.
—
Float level set too high. See Remedy Zc.
. Dirt under fuel inlet needle, See Remedy 2d.
. Bowl vent plugged. Remove fuel bowl and clean bowl vent. Blow out with compressed
air.
. Float is cracked or damaged. Replace float.
. Bowl power screw gasket damaged. Replace gasket.
. Bowl power screw loose. Torgue screw to specifications.
5.4
SECTION 5
FUEL SYSTEM AND GOVERNOR
Adjustment 2. Preliminary settings: Turn the adjusting needles
out (counterclockwise) from lightly bottomed to
NOTE: Carburetor adjustments should be made only the positions shown in the chart.
after the engine has warmed up.
. TURNS
The carburetor is designed to deliver the correct fuei- |
to-air mixture to the engine under all operating condi- CH11 CH12.5 CH14
tions. The main fuel jet (power screw) is calibrated at IDLE 1-1/4 1-1/4 1-3/4
the factory and is adjustable. The idle fuel adjusting
needle is also set at the factory and normally does not HIGH SPEED 1-1/2 1-1/2 1-1/4
need adjustment.
3. Start the engine and run at half-throttle for 5 to 10
If the engine is hard-starting or runs roughly or stalls at minutes to warm up. The engine must be warm
low idle speed, it may be necessary to adjust or serv- before making final settings. Check that the
ice the carburetor. throttle and choke plates can fully open.
4. High idle fuel needle setting: Place the throttle
into the “fast” position. If possible place the en-
gine under ioad. Tum the high idle fuel adjusting
needle in (slowly) until engine speed decreases
and then back out approximately 1/4 turn for best
high-speed performance.
TI
5. Low idle speed setting: Place the throttle control
into the “idle” or “slow” position. Set the low idle
speed to 1500 rpm and *( + 75 rpm) by tuming the
low idle speed adjusting screw in or out. Check
the speed using a tachometer.
«i
Low ] dl e A = >”, I
Fuel Adiusting
Needle
*NOTE: The actual low idie speed depends on the
В High ldie . application — refer to equipment man-
а Needle “3 Be 2 \ ufacturer's recommendations. The recom-
mended low idle speed for basic engines
is 1500 rpm. To ensure best results when
setting the low idle fuel needle the iow
idle speed should not exceed 1500 rpm
Figure 5-2. Adjustable Main Jet Carburetor.
Adjust Carburetor ( + 75 rpm).
1. With the engine stopped turn the low and high idie 6. Low idle fuel needle setting: Place the throttle
fuel adjusting needles in (clockwise) until they into the “idle” or “slow” position. Turn the low idle
bottom lightly.
fuel adjusting needle in (slowly) until engine
speed decreases and then back out approximate-
NOTE: The tip of the idle fuel and high idle fuel ly 1/8 to 1/4 turn to obtain the best low speed per-
adjusting needies are tapered to critica! formance.
dimensions. Damage io the needles and
the seats in carburetor body will result if 7. Recheck the idle speed using a tachometer.
the needles are forced. Readjust the speed as necessary.
5.5
SECTION 5
FUEL SYSTEM AND GOVERNOR
Disassembly
1. Remove the power screw, needle and spring,
main jet, power screw gasket and fuel bowl.
2. Remove the bowl gasket, float shaft, float, and
fuel inlet needle.
3. Remove the low idle fuel adjusting needle and
spring. Remove the low idle speed adjusting
screw and spring.
Further disassembly to remove the welch plug,
fuel inlet seat, throttle plate and shaft, and choke
plate and shatt is recommended only if these
parts are to be cleaned or replaced.
Throttle Lever
Dust Seal
TT,
DD
Throttle Plate Screw(s)
Throttle Plate
Throttle Lever
And Shaft
г
<.
IN
Choke Lever
And Shaft
Ea. —
Ó
Choke Return
Spring
Low Idle Speed Adjusting к
Screw And Spring Ds SN Choke Plate
Low Idle Fuel Adjusting Fuel Inlet à
Needle And Spring Seat Float
Fuel Inlet ~ — Shaft
Needle
Bowl
= um. Gasket
Fuel Bowl
Bowl Retaining
Screw (Gasket
Power Adjusting Needle
Assembly
=
I
Figure 5-3. Carburetor — Exploded View.
5.6
SECTION 5
FUEL SYSTEM AND GOVERNOR
Welch Plug Removal
In order to clean the “off-idle” ports and bowl vent
thoroughly, remove the welch plug covering these ar-
eas.
Use tool no. KO-1018 and the following procedure to
remove the welch plug. See Figure 5-4.
1. Pierce the welch plug with the tip of the tool.
NOTE: To prevent damage to the carburetor, do
not allow the tool to strike the carburetor
body.
2. Pry out the welch plug with the tip of the tool.
Tool #KO1018
Pry Out Plug
Do Not Allow
Tip To Strike
Carburetor Body Pierce Plug
With Tip
Welch Plug
Figure 5-4. Removing Weich Plug.
Fuel Inlet Seat Removal
To remove the fuel inlet seat, pull it out of the carbure-
tor body using a screw, drill bit, or similar tool.
NOTE: Always install a new fuel inlet seat. Do not
reinstall a seat that has been removed.
Choke Shaft Removal
1. Because the edges of the choke plate are bev-
eled, mark the choke plate and carburetor body to
ensure correct reassembly. See Figure 5-5.
Also take note of the choke plate position in bore,
and the position of the choke lever and choke re-
turn spring.
Choke Plate
Carburetor
Воду
Figure 5-5. Marking Choke Plate And
Carburetor Body.
2. Grasp the choke plate with a pliers. Pull it out of
the slot in the choke shaft. See Figure 5-6.
Choke Plate
Figure 5-6. Removing Choke Plate.
3. Remove the choke shaft and choke return spring.
Throttle Shaft Removal
1. Because the edges of the throttle plate are bev-
eled, mark the throttie piate and carburetor body
to ensure correct reassembly.
Also take note of the throttle plate position in
bore, and the position of the throttle lever.
2. Carefully and slowly remove the screws securing
the throttle plate to the throttle shaft. Remove the
throttle plate.
3. File off any burrs which may have been left on the
throttie shaft when the screws were removed. Do
this before removing the throttle shaft from the
carburetor body,
5.7
SECTION 5
FUEL SYSTEM AND GOVERNOR
4. Remove the throttle lever/shaft assembly with
foam dust seal.
Cleaning
WARNING: Flammable Solvents!
A Carburetor cleaners and solvents are
extremely flammable. Keep sparks,
flames, and other sources of ignition
away from the area. Follow the cleaner
manufacturer's warnings and instruc-
tions on its proper and safe use. Never
use gasoline as a cleaning agent.
All parts should be cleaned thoroughly using a carbu-
retor cleaner (such as acetone). Make sure all gum
deposits are removed from the following areas:
e Carburetor body and bore; especially the areas
where the throttle plate, choke plate and shafts
are seated.
e ldle fuel and “off-idle” ports in carburetor bore,
power screw, bowl vent, and fuel inlet needle
and seat.
NOTE: These areas can be cleaned with a piece
of fine wire in addition to cleaners. Be
careful not to enlarge the ports, or break
the wire inside the ports. Blow out ali pas-
sages with compressed air.
e Float and float hinge.
e Fuel bowl.
e Throttle plate, choke plate, throttle shaft, and
choke shaft.
NOTE: Do not submerge the carburetor in cleaner or
solvent when fiber, rubber, or foam seals or
gaskets are installed. The cleaner may dam-
age these components.
Inspection
Carefully inspect all components and replace those
that are worn or damaged.
e Inspect the carburetor body for cracks, holes, and
other wear or damage.
® Inspect the float for cracks, holes, and missing or
damaged float tabs. Check the float hinge and
shaft for wear or damage.
® Inspect the fuel inlet needle and seat for wear or
damage.
® Inspect the tip of the low idle fuel adjusting needle
and power screw needle for wear or grooves.
e Inspect the throtile and choke shaft and plate as-
semblies for wear or excessive play.
Repair
Always use new gaskets when servicing or reinstalling
carburetors. Repair kits are available which include
new gaskets and other components. These Kits are
described below.
Components such as the throttle and choke shaft as-
semblies, throttle plate, choke plate, tow idle fuel nee-
dle, power screw, and others, are available sepa-
rately.
Always refer to the Parts Manual for the engine being
serviced to ensure the correct repair kits and replace-
ment parts are ordered.
Carburetor Repair Kit Contains:
Qty. Description
Heat Deflector Gasket
Air Cleaner Base Gasket
Bowl Gasket
Bowl Retainer Gasket
Welch Plug
Fuel Inlet Needle Valve
Fuel Inlet Valve Seat
— — йо ой её =
5.8
SECTION 5
FUEL SYSTEM AND GOVERNOR
Float Assembly Kit Contains: 4. Apply finger pressure to the throttle lever/shaft to
keep it firmly seated against the pivot in the car-
Qty. Description buretor body. Rotate the throttle shaft until the
1 Float Assembly throttle plate Closes the bore around its entire pe-
1 Float Shaft rimeter; then tighten the screws. See Figure 5-7.
5. Operate the throttle lever. Check for binding be-
Adjustable Power Screw Kit Contains: tween the throttle plate and carburetor bore.
Loosen the screws and adjust the throttle plate as
Qty. Description necessary.
1 Power Screw Assembly ‚ si
; Bowl Retainer Gasket Torque the screws to 0.9/1.4 Nem (8/12 Ibfein).
Choke Shaft Installation
Reassembly 1. Install the choke return spring to the choke shaft.
2. Insert the choke iever with return spring into the
Throttle Shaft Installation carburetor body.
3. Rotate the choke lever approximately 1/2 turn
1. Install the foam dust seal on the throttle shaft. counterclockwise. Make sure the choke return
spring hooks on the carburetor body.
buretor body. Position the cutout portion of the during disassembly. Insert the choke plate into the
shaft so it faces the carburetor mounting flange. slot in the choke shaft. Make sure the choke shaft
is locked between the tabs on the choke plate.
3. install the throttle plate to the throttle shaft. Make
sure the plate is positioned properly in the bore as
noted and marked during disassembly. Apply
Loctite ® no. 609 to the threads of the throttie Press the fuel inlet seat into the bore in carburetor
plate retaining screws. install the screws so they body until it bottoms.
are slightly loose.
Fuel Inlet Seat Installation
Welch Plug Installation
Appiy Pressure When Use tool no. KO-1017 and install new plugs as fol-
Tightening Screws lows:
\ 1. Position the carburetor body with the welch plug
` cavity to the top.
2. Place a new welch plug into the cavity with the
raised surface up.
3. Use the end of the tool that is about the same size
as the plug and flatten the plug. Do not force the
plug below the surface of the cavity. See Figure
Figure 5-7. installing The Throttle Lever/Shaft. 5-8.
5.9
SECTION 5
FUEL SYSTEM AND GOVERNOR
4. After the plug is installed, seal it with glyptal (or an
equivalent sealant). Allow the sealant to dry.
NOTE: If a commercial sealant is not available, fin-
gernail polish can be used.
Tool +X01017
Carburetor Body
TI A New Welch Plug
Fuel Inlet
Needle
Figure 5-8. Installing Welch Plug.
Carburetor Reassembly
1. Install the low idle speed adjusting screw and
spring.
2. Install the low idle fuel adjusting needle and
spring. Turn the adjusting needle in (clockwise)
until it bottoms lightly.
NOTE: The tip of the idle fuel adjusting needle is
tapered to critical dimensions. Damage to
the needle and the seat in carburetor
body will result if the needle is forced.
3. Turn the low idle fuel adjusting needie out (coun-
terclockwise) as specified in the “Adjustment”
portion of this section.
4. Insert the fuel inlet needle into the float. Lower the
float/needle into the carburetor body. See Figure
5-9.
Install the float shaft.
Figure 5-9. Installing Float And Fuel
Inlet Needle.
5. Install the bow! gasket, fuel bowl, bowl! retainer
gasket, and power screw.
Torque the power screw to: 5.1/6.2 Nem (45/55
Ibfein).
High Altitude Operation
When operating the engine at altitudes of 1830 m
(6000 ft) and above, the main fuel mixture tends to get
Overrich. An overrich mixture can cause conditions
such as black, sooty exhaust smoke, misfiring, loss of
speed and power, poor fuel economy, and poor or
siow governor response.
To compensate for the effects of high altitude, a spe-
cial high altitude main fuel jet can be installed. High
altitude jets are sold in kits which include the jet and
necessary gaskets. Refer to the Parts Manual for the
engine being serviced for the correct kit number.
GOVERNOR
These engines are equipped with a centrifugal fly-
weight mechanical governor. it is designed to hold the
engine speed constant under changing load condi-
tions. The governor gear/flyweight mechanism is
mounted inside the crankcase and is driven off the
gear on the camshaft.
Operation
Centrifugal force acting on the rotating governor gear
assembly causes the flyweights to move outward as
5.10
SECTION 5
FUEL SYSTEM AND GOVERNOR
speed increases and inward as speed decreases. As
the flyweights move outward, they cause the reguiat-
ing pin to move outward.
The regulating pin contacts the tab on the cross shaft,
causing the shaft to rotate when the engine speed
changes. One end of the cross shaft protrudes through
the side of the crankcase. Through external linkage
attached 1o the cross shaft, the rotating action is trans-
mitted to the throttle lever of the carburetor.
When the engine is at rest, and the throttle is in the
“fast” position, the tension of the governor spring
holds the throttle plate open. When the engine is oper-
ating (the governor gear assembly is rotating}, the
force applied by the regulating pin against the cross
shaft tends to close the throttle plate. The govemor
spring tension and the force applied by the regulating
pin are in “equilibrium” during operation, holding the
engine speed constant.
When load is applied and the engine speed (and gov-
enor gear speed) decreases, the governor spring ten-
sion moves the governor arm to open the throttie plate
wider. This allows more fuel into the engine; increas-
ing engine speed. (This action takes place very rap-
idly, so a reduction in speed is hardly noticed.) As the
speed reaches the governed setting, the govemor
spring tension and the force applied by the regulating
pin will again be in equilibrium. This maintains the en-
gine speed at a relatively constant level.
The govemed speed setting is determined by the po-
sition of the throttle control. lt can be variable or con-
stant, depending on the application.
Initial Adjustment
Make this initial adjustment whenever the governor
arm is Ioosened or removed from the cross shaft. To
ensure proper setting, make sure the throttle linkage is
connected to the governor arm and the throttle lever
on the carburetor. See Figure 5-10.
E... ABE Governor Lever №8
= À
he J
+ pn
a на
BE Cross —
Figure 5-10. Initial Governor Adjustment.
1. Puli the governor lever away from the carburetor
{wide open throttle).
2. Insert a nail in the cross shaft hole or grasp the
cross shaft with a pliers and turn the shaft coun-
terclockwise as far as it will go.
3. Tighten the hex nut securely.
Sensitivity Adjustment
Govemor sensitivity is adjusted by repositioning the
governor spring in the holes in the governor lever. If
speed surging occurs with a change in load, the gov-
ernor is set too sensitive. If a big drop in speed occurs
when normal toad is applied, the governor should be
set for greater sensitivity.
5.11
SECTION 5
FUEL SYSTEM AND GOVERNOR
Remote Throttle and Choke Adjustment
1. Adjust the throttle lever. See this section.
2. Install remote throttle cable in hole in the throttle
lever. See Figure 5-11.
5 Remote Choke
Lever
Remote
Lever
и
Figure 5-11. Remote Throttle And Choke
Adjustment.
. Install remote choke cable in hole in the choke
lever.
. Secure remote cables loosely with the cable
clamps.
. Position the throttle cable so that the throttle lever
is against stop.
. Tighten the throttle cable clamp.
. Position the choke cable so that the carburetor
choke plate is fully closed.
. Tighten the choke cable clamp.
. Check carburetor idle speed. See Adjust Carbure-
tor in this section.
5.12
COMMAND 11, 12.5, 14
SECTION 6
LUBRICATION SYSTEM
OIL RECOMMENDATIONS
Using the proper type and weight of oil in the crank-
case is extremely important. So is checking oil daily
and changing oil regularly. Failure to use the correct
oil, or using dirty oil, causes premature engine wear
and failure.
Oil Type
Use high-quality detergent oil of API (American Pe-
troleum institute) service class SF or SG. Select the
viscosity based on the air temperature at the time of
operation as shown in the following table.
Recommended SAE Viscosity Grades
10W-30, 10W-40
TEMPERATURE RANGE EXPECTED BEFORE NEXT GIL CHANGE
CHECK OIL LEVEL
The importance of checking and maintaining the
proper cil level in the crankcase cannot be overem-
phasized. Check oil BEFORE EACH USE as follows:
1. Make sure the engine is stopped, level, and is
cool so the oil has had time to drain into the
sump.
NOTE: Using other than service class SF or SG oil or
extending oil change intervals longer than rec-
ommended can cause engine damage.
A logo or symbol on oil containers identifies the AP
service class and SAE viscosity grade. See Figure
6-1.
Figure 6-1. Qil Container Logo.
2. To keep dirt, grass clippings, etc., out of the en-
gine, clean the area around the oil fill cap/dipstick
before removing it.
3. Remove the oil fill cap/dipstick; wipe oil off. Rein-
sert the dipstick into the tube and seat the oil fill
cap on the tube. See Figure 6-2.
6.1
don
2
SECTION 6
LUBRICATION SYSTEM
Figure 6-2. Checking Oil Level.
4. Remove the dipstick and check the oil ievel.
The oil level should be up to, but not over, the “F”
mark on the dipstick. See Figure 6-3.
|
Operating
Range
|
L
Figure 6-3. Oil Level Dipstick.
5. If the level is low, add oil of the proper type, up to
the “F” mark on the dipstick. Always check the
level with the dipstick before adding more oil.
NOTE: To prevent extensive engine wear or damage,
always maintain the proper oil level in the
crankcase. Never operate the engine with the
oil level below the “I” mark or over the “Е”
mark on the dipstick.
Oil Sentry ™
Some engines are equipped with an optional Gil Sen-
try oil pressure monitor. If the oil pressure gets low, Cil
Sentry will either shut off the engine or activate a warn-
ing signal, depending on the application.
NOTE: Make sure the oil level is checked BEFORE
EACH USE and is maintained up to the “F”
mark on the dipstick. This includes engines
equipped with Oil Sentry.
CHANGE OIL AND OIL FILTER
Change Oil
For a new engine, change oil after the first 5 hours of
operation. Thereafter, change oil after every 100
hours of operation.
For an overhauled engine or those rebuilt with a
new short block, use 70W-30-weight service class SF
oil for the first 5 hours of operation. Change the oil
after this initial run-in period. Refill with service class
SF oil as specified in the “Viscosity Grades” table.
Change the oil while the engine is still warm. The oil
will flow freely and carry away more impurities. Make
sure the engine is level when filling, checking, and
changing the oil.
Change the oil as follows (see Figure 6-4):
1. Remove the oil drain plug and oil fill cap/dipstick.
Be sure to allow ample time for complete drain-
age.
2. Reinstall the drain plug. Make sure it is tightened
to 13.6 N-m (10 Ibf-ft) torque.
3. Fill the crankcase, with new oil of the proper type,
to the “F” mark on the dipstick. Always check the
level with the dipstick before adding more oil.
4. Reinstall the oil fill cap/dipstick.
NOTE: To prevent extensive engine wear or damage,
always maintain the proper oil level in the
crankcase. Never operate the engine with the
oil level below the “L” mark or over the “F”
mark on the dipstick.
6.2
SECTION 6
LUBRICATION SYSTEM
6. Reinstall the drain plug. Torque the drain plug to
7.3/9.0 N-m (65/80 Ibf-in).
7. Fill the crankcase with new oil as instructed under
“Change Oil.” Add an additional 0.24 L (1/2 pint)
of oil for the filter capacity.
8. Start the engine and check for oil leaks. Correct
any leaks before placing the engine into service.
FULL PRESSURE LUBRICATION SYSTEM
Operation
- | A This engine uses a full-pressure lubrication system.
— J A This system delivers oil, under pressure, to the crank-
“a
Oil Sentry: shaft, camshaft, balance shaft, and connecting rod
(Option) bearing surfaces. In addition to lubricating the bearing
surfaces, the lubrication system operates the hydraulic
valve lifters.
Oil Filter
A high efficiency gerotor oil pump is located in the
Figure 6-4. Oil Drain Plug (Starter Side Shown, closure plate and is driven directly by the balance
Also Located Behind QOit Filter), Oil Filter, shaft. The oil pump maintains high oil flow and oil
And Optional Oil Sentry Switch. pressure, even at low speeds and high operating tem-
но: peratures. A pressure relief valve in the closure plate
Change Oil Filter limits the maximum pressure of the system.
Replace the oil filter every other oil change (every
200 hours of operation). Always use a genuine Koh-
ler oil filter.
For a cold engine at start up, the oil pressure can go
up to 60 psig. For a warm (norma! operating tempera-
ture) engine at idle speed, the oil pressure can go
Replace the oil filter as follows: down to 12 psig.
1. Drain the oil from the engine crankcase.
2. Allow the oil filter to drain. Service
The oil pump rotors can be serviced without removing
3. Remove the old filter and wipe off the filter the closure plate. Remove the oil pump cover on the
adapter. | РТО side of closure plate to service the rotors.
4. Apply a thin coating of new oil to the rubber gas- The closure plate must be removed to service the oil
ket on the replacement oil filter. pickup and oil pressure relief valve.
5. Install the replacement oí! filter to the filter adapter. See Figures 6-5, 6-6, and 6-7. Also refer to the “Dis-
Turn the oil filter clockwise until the rubber gasket assembly” and “Reassembly” sections for lubrication
contacts the filter adapter, then tighten the filter an system components removal and installation proce-
additional 1/2 turn. dures.
6.3
SECTION 6
LUBRICATION SYSTEM
Figure 6-6. Oil Pickup.
=iW— Hex Socket
4 Y Screw
Relief Valve Bracket
Spring
Figure 6-7. Oil Pressure Relief Valve Components.
OIL FILTER
These engines are equipped with a full-flow oil filter.
See Figure 6-8.
The oil filter helps remove sludge and other combus-
tion by-products from the oil. It also extends the oil
change interval and cools the oil.
Oil Sentry}
(Option)
Oil Filter
Figure 6-8. Oil Filter And Oil Sentry™.
OIL SENTRY™ OIL PRESSURE MONITOR
Some engines are equipped with an optional Oil Sen-
try oil pressure monitor. See Figure 6-8. Oil Sentry will
either stop the engine or activate a “low oil” warning
light, if the oil pressure gets low. Actual Oil Sentry use
will depend on the engine application.
Operation
The pressure switch is designed to break contact as
the oil pressure increases and make contact as the oil
pressure decreases. At oil pressures above approx.
3.0 to 5.0 psig., the switch contacts open. At oil pres-
sures below approx. 3.0 to 5.0 psig., the switch con-
tacts close.
On staticnary or unattended applications (pumps,
generators, etc.}, the pressure switch can be used to
ground the ignition module 1o stop the engine.
On vehicular applications {lawn tractors, mowers,
etc.), the pressure switch can be used to activate a
“low oil” warning light.
NOTE: Oil Sentry is not a substitute for checking the
oil level BEFORE EACH USE. Make sure the
oil leve] is maintained up to the “F” mark on
the dipstick.
6.4
SECTION 6
LUBRICATION SYSTEM
Installation
The pressure switch is installed in the oil filter adapter,
in one of the main oil galleries of the closure plate
(see Figure 6-8). On engines not equipped with Cil
Sentry, the installation hole is sealed with a 1/8-27
N.PT.F pipe plug.
To install the Oil Sentry switch to the oil filter adapter
of closure plate:
1. Apply Loctite® #592 pipe sealant with teflon (or
equivalent} to the threads of the switch.
2. Install the switch into the tapped hole in oil filter
adapter.
Torque the switch to 7.9 N»m (70 Ibf-in).
Testing
The Oil Sentry pressure monitor is a normally closed
type switch. It is calibrated to open (break contact)
with increasing pressure ang close (make contact)
with decreasing pressure within the range of 3.0/5.0
psig.
Compressed air, a pressure regulator, pressure gauge,
and a continuity tester are required to test the switch.
1. Connect the continuity tester across the blade ter-
minal and the metal case of switch. With 0 psig
pressure applied to the switch, the tester should
indicate continuity (switch closed).
2. Gradually increase the pressure to the switch. The
tester should indicate a change to no continuity
(switch open) as the pressure increases through
the range of 3.0/5.0 psig.
The switch should remain open as the pressure is
increased to 90 psig maximum.
3. Gradually decrease the pressure to the switch.
The tester should indicate a change to continuity
(switch closed) as the pressure decreases
through the range of 3.0/5.0 psig; approaching 0
psig.
If the switch does not operate as specified, replace
the switch.
6.5
COMMAND 11, 12.5, 14
SECTION 7
RETRACTABLE STARTER
CAUTION: Spring Under Tension!
Retractable starters contain a powerful, flat wire recoil spring that is under tension.
Do not remove the center screw from the starter until the spring tension is released.
Removing the center screw before releasing spring tension, or improper starter dis-
assembly, can cause the sudden and potentially dangerous release of the spring.
Always wear safety goggles when servicing retractable starters — full face protection is
recommended.
To ensure personal safety and proper starter disassembly and reassembly, follow the
procedures in this section carefully.
TO REMOVE STARTER
Drive cup
/ 1. Remove the five hex flange screws securing the
starter to blower housing.
WO Center screw
_ A Pawl (dog) repair kit
Spring and keeper
2. Remove the starter.
TO INSTALL STARTER
1. Install the retractable starter and five hex flange
screws to blower housing. Leave the screws
slightly loose.
Starter Housing
Recoil start handle 2. Pull the starter handle out until the pawls engage
in the drive cup. Hold the handle in this position
Figure 7-1. Retractable Starter — Exploded View. and tighten the screws securely. See Figure 7-2.
7.1
SECTION 7
RETRACTABLE STARTER
Figure 7-2. Installing Retractable Starter.
ROPE REPLACEMENT
The rope can be replaced without complete starter
disassembly.
1. Remove the starter from the engine blower hous-
Ing.
2. Pull the rope out approx. 12” and tie a temporary
(slip) knot in it to keep it from retracting into the
starter. See Figure 7-3.
5. When all spring tension on the starter pulley is
released, remove the rope from pulley.
6. Tie a single knot in one end of the new rope.
7. Rotate the pulley counterclockwise (when viewed
from pawl side of pulley) until the spring is tight.
(Approx. 6 full tums of pulley.)
8. Rotate the pulley clockwise until the rope hole in
pulley is aligned with rope guide bushing of starter
housing.
NOTE: Do not allow the pulley/spring to unwind.
Enlist the aid of a helper if necessary, or
use a C-clamp to hoid the pulley in posi-
tion.
9. insert the new rope through the rope hole in starter
pulley and rope guide bushing of housing. See
Figure 7-4.
Slip Knot Handle
Knot
Rope Retainer
From Rotating PP Rope Guide
= Sey susning
a Rope Hole
NA Un nope He
%
1 PE
4. :.. `` —
3 7 * i] Tas "a A “`` я ый A
- Ld
—
a
ze
Figure 7-3. Removing Starter Handie.
3. Remove the rope retainer from inside the starter
handie. Untie the single knot and remove the rope
retainer and handle.
4. Hold the pulley firmly and untie the slip knot. Al-
low the puliey to rotate slowly as the spring ten-
sion is released.
Figure 7-4. installing Rope.
10. Tie a slip knot approx. 12” from the free end of
rope. Hold the puliey firmly and allow it to rotate
slowly until the slip knot reaches the guide bush-
ing of housing.
11. Slip the handle and rope retainer onto the rope.
Tie a single knot at the end of the rope. Install the
rope retainer into the starter handie.
12. Untie the slip knot and pull on the handle until the
rope is fully extended. Slowly retract the rope into
the starter.
When the spring is properly tensioned, the rope
will retract fully and the handie will stop against
the starter housing.
7.2
SECTION 7
RETRACTABLE STARTER
PAWLS (DOGS) REPLACEMENT
The starter must be completely disassembled to re-
place the starter pawls. A pawl repair Kit is available
which includes the following components:
Pawl Repair Kit Contains:
Qty. Description
Paw! Retainer
Center Screw
Pawl (Dog) Spring
Brake Spring
Starter Pawl (Dog)
Brake Washer
Figure 7-5. Center Screw, Washer And
Pawl Retainer.
— 1 ND + = № La —
Washer
DISASSEMBLY
CAUTION: Spring Under Tension!
Do not remove the center screw from
A Starter until the spring tension is re-
leased. Removing the center screw be-
fore releasing spring tension, or im-
proper starter disassembly, can cause
the sudden and potentially dangerous
release of the spring. Follow these in-
structions carefully to ensure personal
safety and proper starter disassembly.
Make sure adequate face protection is
worn by all persons in the area.
1. Release spring tension and remove the handle
and starter rope. (Refer to "Hope Replacement”,
steps 2 through 5 above.)
2. Remove the center screw, washer, and pawl re-
tainer. See Figure 7-5.
3. Remove the brake spring and brake washer. See
Figure 7-6.
4. Carefully note the positions of the pawis and pawl
springs before removing them.
Remove the pawis and paw! springs from ihe
starter pulley.
Figure 7-6. Brake Spring And Washer, Pawls,
And Pawi Springs.
. Rotate the pulley clockwise 2 full turns. This will
ensure the spring is disengaged from the starter
housing.
. Hold the pulley into the starter housing. Invert the
pulley/housing so the pulley is away from your
face, and away from others in the area.
. Rotate the pulley slightly from side to side and
carefully separate the pulley from the housing.
See Figure 7—7.
if the pulley and the housing do not separate eas-
ily, the spring could be engaged in the starter
housing, or there is still tension on the spring. Re-
turn the pulley to the housing and repeat step 5
before separating the pulley and housing.
7.3
SECTION 7
RETRACTABLE STARTER
Housing
Figure 7-7. Removing Pulley From Housing.
8. Note the position of the spring and keeper assem-
bly in the pulley. See Figure 7-8.
Remove the spring and keeper assembly from the
pulley as a package.
CAUTION: Spring Under Tension!
A
Do not remove the spring from the
keeper. Severe personal injury could
result from the sudden uncoiling of the
spring.
Rope Hole
in Pulley
Outer
Spring
Hook
Spring & Keeper
Figure 7-8. Position Of Spring And
Keeper in Pulley.
INSPECTION AND SERVICE
1. Carefully inspect the rope, pawils, housing, center
screw, and other components for wear or damage.
2. Replace all worn or damaged components. Use
only genuine Kohler replacement parts as speci-
fied in the Parts Manual. All components shown in
Figure 7-1. are available as service parts. Do not
use nonstandard parts.
3. Do not attempt to rewind a spring that has come
out of the keeper. Order and install a new spring
and keeper assembly.
4, Clean all old grease and dirt from the starter com-
ponents. Generously lubricate the spring and cen-
ter shaft with any commercially available bearing
grease.
REASSEMBLY
1. Make sure the spring is well lubricated with
grease. Place the spring and keeper assembly
inside the pulley (with spring towards pulley). See
Figure 7-8.
2. Install the puliey with spring and keeper assembly
into the starter housing. See Figure 7-9.
Make sure the pulley is fully seated against the
starter housing. Do not wind the pulley and recoil
spring at this time.
Housing
Figure 7-9. Installing Pulley And Spring
Into Housing.
3. Install the pawils springs and pawis into the starter
pulley. See Figure 7-10.
7.4
SECTION 7
RETRACTABLE STARTER
5. Lubricate the brake spring sparingly with grease.
Place the spring on the plain washer. (Make sure
the threads in center shaft remain clean, dry, and
free of grease and oil.)
6. Apply a small amount of Loctite® #271 to the
threads of the center screw. Install the center
screw, with washer and retainer, to the center
shaft. Torque the screw to 7.4/8.5 Nem (65/75
Ibf-in).
Зы a 7. Tension the spring and install the rope and handle
Figure 7-10. installing Pawls And Pawl Springs. as instructed in steps 6 through 12 under “Rope
Replacement” above.
4, Place the brake washer in the recess in starter
pulley; over the center shaft. 8. Install the starter to the engine blower housing.
7.5
COMMAND 11, 12.5, 14
SECTION 8
ELECTRICAL SYSTEM AND COMPONENTS
This section covers the operation, service, and repair of the electrical system and electrical sys-
tem components.
Major electrical systems and components covered in this section include the spark plug, battery,
ignition system and ignition module, battery charging systems, electric starters, and Oil Sentry ™
oil pressure switch.
SPARK PLUG 3. Check the gap using a wire feeler gauge. Adjust
the gap to 1.02 mm (0.040 in) by carefully bend-
Engine misfire or starting problems are often caused ing the ground electrode. See Figure 8-1.
by a spark plug that is in poor condition or with an
Improper gap setting.
This engine is equipped with the following spark plug: 4. Reinstall the spark plug into the cylinder head.
Torque the spark plug to 38.0/43.4 N.m
(28/32 Ibf-ft).
Type: Champion® RC12YC (or equivalent) .
Gap: 1.02 mm (0.040 in) K
Thread Size: 14mm
Reach: 19.1 mm (3/4 in) Wire Gauge
Hex Size: 15.9 mm (5/8 in)
Spark Plug Service
Every 100 hours of operation, remove the spark plug,
check its condition, and reset the gap or replace with
a new plug as necessary.
1. Before removing the spark plug, clean the area
around the base of the plug to keep dirt and de-
bris out of the engine.
2. Remove the plug and check its condition. Replace
the plug if worn or reuse is questionable. |
Ground
NOTE: Do not clean the spark plug in a machine Electrode A
using abrasive grit. Some grit could re- 1.02 mm (0.040 in) Gap
main in the spark plug and enter the en-
gine causing extensive wear and damage. Figure 8-1. Servicing Spark Plug.
8.1
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Inspection
Inspect the spark plug as soon as it is removed from
the cylinder head. The deposits on the tip are an indi-
cation of the general condition of the piston rings,
valves, and carburetor.
Normal and fouled plugs are shown in the following
photos.
Carbon Fouled: Soft, sooty, black deposits indicate
incomplete combustion. Incomplete combustion is
usually caused by overrich carburetion, weak ignition,
or poor compression.
Normal: A piug taken from an engine operating under
normal conditions will have light tan or gray colored
deposits. If the center electrode is not worn, a plug in
this condition could be regapped and reused.
Worn: On a wom plug, the center electrode will be
rounded and the gap will be eroded .010” or more
than the correct gap. Replace a wom spark plug im-
mediately.
8.2
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Wet Fouled: A wet plug is caused by excess fuel, or
oil in the combustion chamber. Excess fuel could be
caused by operating the engine with too much choke.
Oil in the combustion chamber is usually caused by
worn piston rings or valve guides.
Chalky White Deposits: Chalky white colored depos-
its indicate overheating. This condition is usually ac-
companied by excessive gap erosion. A clogged
grass screen, clogged cooling fins, and lean carbure-
tion are some causes of overheating.
BATTERY
A 12-volt battery with a rating of approximately 32-amp
hours/250 cold cranking amps. is normally used. Refer
to the operating instructions of the equipment this en-
gine powers for specific information.
If the battery charge is not sufficient to crank the en-
gine, recharge the battery.
NOTE: Do not attempt to “jump start” the engine with
another battery. Starting the engine with bat-
teries larger than those recommended can
burn out the starter motor.
Battery Charging
WARNING: Dangerous Acid, Explosive Gases!
Batteries contain sulfuric acid. To pre-
vent acid burns, avoid contact with
Skin, eyes, and clothing. Batteries pro-
duce explosive hydrogen gas while be-
ing charged. To prevent a fire or expio-
sion, charge batteries only in well venti-
lated areas. Keep sparks, open flames,
and other sources of ignition away from
the battery at all times. Keep batteries
out of the reach of children. Remove ali
jewelry when servicing batteries.
Before disconnecting the negative (-)
ground cable, make sure all switches
are OFF. If ON, a spark will occur at the
ground cable terminal which could
cause an explosion if hydrogen gas or
gasoline vapors are present.
Battery Maintenance
Regular maintenance will ensure the battery will ac-
cept and hold a charge.
1. Regularly check the level of electrolyte. Add dis-
tilled water as necessary to maintain the recom-
mended level.
NOTE: Do not overfill the battery. Poor perform-
ance or early failure due to loss of electro-
lyte will result.
8.3
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
2. Keep the cables, terminals, and external surfaces
of battery clean. A build-up of corrosive acid or
grime on the external surfaces can self-discharge
the battery. Self-discharging happens rapidly
when moisture is present.
3. Wash the cables, terminals, and external surfaces
with a baking soda and water solution. Rinse thor-
oughly with clear water.
NOTE: Do not allow the baking soda solution to
enter the cells as this will destroy the
electrolyte.
Battery Test
Test the battery voltage by connecting D.C. voltmeter
across the battery terminals — crank the engine. If the
battery drops below 9 volts while cranking, the battery
Is discharged or faulty. Refer to Figure 8-2.
D.C. Voltmeter
Battery
Figure 8-2. Checking Battery Voltage.
ELECTRONIC MAGNETO IGNITION
SYSTEM
These engines are equipped with a dependable elec-
tronic magneto ignition system. The system consists
of the following components:
e A magnet assembly which is permanently affixed
to the flywheel.
e An electronic magneto ignition module which
mounts on the engine crankcase.
e À kill switch (or keyswitch) which grounds the
module to stop the engine.
e A spark plug.
Operation
As the flywheel rotates and the magnet assembly
moves past the ignition module, a low voltage is in-
duced in the primary windings of the module. When
the primary voltage is precisely at its peak, the mod-
ule induces a high voltage in its secondary windings.
This high voltage creates a spark at the tip of the
spark plug. This spark ignites the fuel-air mixture in the
combustion chamber.
The timing of the spark is automatically controlled by
the module. Therefore, other than periodically check-
ing/repiacing the spark plug, no maintenance, timing,
or adjustmenis are necessary or possible with this
system.
In the event starting problems should occur which are
not corrected by replacing the spark piug, refer to the
following “Troubleshooting Guide” for trouble analysis
procedures.
8.4
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
High Tension Lead (C)
Spark
Plug
0.20/0.30 mm Ignition
(0.008/0.012 in) Module
Air Gap
+ | Kill Termina! (8)
O
Ú
Magnet
r—— =="
но — — — -
6
Kill Switch — Lamination (A)
— Or OFF
o
A
ил Position Of
Keyswitch
Figure 8-3. Electronic Magneto Ignition System.
Ignition System
Troubleshooting Guide
The following guide will help locate and correct igni- NOTE: Use a low-voltage (2 volts or less) ohmmeter
tion system-related starting problems. This procedure when ohmmeter is required. Always zero ohm-
uses a simple tester which can easily be made by the meter on each scale before testing to ensure
serviceman. Refer to Section 2—“Special Tools” for accurate readings.
ignition system tester construction details.
8.5
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Problem Test Conclusion
1. Make sure the spark plug lead is connected to the
spark plug.
2. Check the condition of spark plug. Make sure gap is 2. If plug is in good condition, check/adjust gap and reinstall.
set to 1.02 mm (0.080 in)
3. Check ignition module using test plug.(Refer to Section | 3. If visible and audible sparks are produced, the ignition
2— "Special Tools.” module is OK.
a. Remove the high-tension lead from the engine If visible and audible sparks are not produced:
spark plug and connect them to the test plug. a | .
a. Make sure the engine ignition switch, kill switch, or
NOTE: To maintain engine speeds normally ob- keyswitch is in the “run” position.
tained during cranking, do not remove the engine b. Check wires and terminals of ignition module and
spark plug. other components for accidental grounding and
b. Make sure the engine ignition switch, kilt switch, or damaged insulation.
keyswitch is In the “run” position. с. [If wires and terminals are OK, the ignition module is
ENGIN E e. Crank the engine and observe the test plug. Vis- probably faulty and should be replaced. Test module
START ible and audible sparks should be produced. further using an ohmmeter (Test 4).
4b. Measure the resistance of module secondary using an if the resistance is low or 0 ohms, the module secondary
ohmmeter (see Figures 8-3 and 8-4): is shorted. Replace the module.
Connect one ohmmeter lead to laminations (A). Con- if the resistance is high or infinity ohms, the module
nect the other lead to the spark plug terminal of high- secondary is open. Replace the module.
tension lead (C). With the ohmmeter leads connected
in this manner, the resistance of secondary should be If the resistance is within the specified range, the module
7,900 to 10,850 ohms, secondary is OK.
NOTE: This test cannot be performed unless module
has been fired at least once.
8.6
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
ELECTRICAL SYSTEMS
BATTERY CHARGING SYSTEMS
This engine is equipped with a 15 Amp regulated bat-
tery charging system.
Refer to the following wiring diagram and
troubleshooting guide to test and service this system.
NOTE: Observe the following guidelines to prevent
damage to the electrical system and compo-
nents.
у
o
x Xe
5 A N
Figure 8-4. Testing Module Secondary.
1. Make sure the battery polarity IS correct. A
negative (-) ground system is used.
2. Disconnect the rectifier-regulator leads and/or
wiring hamess plug before doing electric
welding on the equipment powered by the
engine. Also disconnect other electrical ac-
cessories in common ground with the engine.
Ignition Module
Removal And Installation
Refer to the Disassembly and Reassembly sections 3. Prevent the stator (AC) leads from touching or
for complete ignition module removal and installation shorting while the engine is running. This
procedures. could damage the stator.
8.7
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Electric Start Engines
15 Amp Battery Charging System
LL. Ground-To-Kill Lead (White)
(Violet)
= у Spark
© © Ignition
Module
So B (Red)
AC =
Keyswitch о Fywieel
В+ O Stator
Optional || o AC
Fuse
Rectifier-
| i Regulat
Optional Optional М egulator
Oil Sentry — Ammeter
Switch —
(Indicator Light
Optional
Oil Sentry _ + 9
Switch o o Oo 5 |
(Shutdown) | P starter
Battery Solenoid
Figure 8-5. Wiring Diagram — Electric Start Engines/15 Amp Battery Charging System.
15 Amp Stator
A.C. Leads
Rectifier-Regulator
Figure 8-6. 15 Amp Stator And Rectifier-Regulator.
8.8
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Troubleshooting Guide —
15 Amp Battery Charging System
NOTE: Zero ohmmeters and voltmeters on each scale to ensure accurate readings. Voltage tests
should be made with the engine running at 3600 rpm —no load. The battery must be fully
charged.
Problem Test Conclusion
1. Insert an ammeter in the B+ lead from rectifier- 1. If the charge rate increases when load is applied,
regulator. With engine running at 3600 rpm and B+ the charging system is OK and the battery was fully
connected, measure the voltage from B+ (at termi- charged.
nal on rectifier-regulator) to ground using a DC volt-
meter. if the charge rate does not increase when load is
applied, test the stator and rectifier-regulator (tests 2
И the voltage is 13.8 volts or more, place a mini- and 3).
mum load of 5 amps* on the battery to reduce the
voitage. Observe the ammeter.
*NOTE: Turn on lights (if 60 watts or more) or place a
2.5 ohm, 100 watt resistor across the battery
terminals.
2. Remove the connector from the rectifier-regulator. 2. If the voltage is 28 volts or more, the stator is OK.
With the engine running at 3600 rpm, measure the The rectifier-regulator is faulty. Replace the rectifier-
No AC voltage across stator leads using an AC voltme- regulator.
Charge ter.
To If the voltage is less than 28 volts, the stator is
Battery probably faulty. Test stator further using an ohmme-
ter (test 3).
3a. With the engine stopped, measure the resistance 3a. If the resistance is 0.1/0.2 ohms, the stator is OK.
across stator leads using an ohmmeter.
If the resistance is infinity ohms, the stator is open.
Replace the stator.
3b. With the engine stopped, measure the resistance 3b. If the resistance is infinity ohms (no continuity), the
from each stator lead to ground using an ohmme- stator is OK {not shorted to ground).
ter.
If resistance (or continuity) is measured, the stator
leads are shorted to ground. Replace the stator.
1. With the engine running at 3600 rpm, measure the 1. If the voltage is 14.7 volts or less, the charging sys-
voltage from B+ lead to ground using a DC voltme- tem is OK; the battery is unable to hold a charge, or
Battery ter. there is a bad connection between the rectifier-regu-
Continuously lator and battery. Check the wiring hamess; service
Tigh Ra at or replace the battery as necessary.
If the voltage is more than 14.7 volts, the rectifier-
regulator is is faulty. Replace the rectifier-regulator.
ELECTRIC STARTER
NOTE: Do not crank the engine continuously for more
than 10 seconds at a time. If the engine does
not start, allow a 60-second cool-down period
between starting attempts. Failure to follow
these guidelines can burn out the starter mo-
tor.
8.9
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
NOTE: If the engine develops sufficient speed 10 dis- off the starter immediately. Do not make fur-
engage the starter but does not keep running ther attempts to start the engine until the con-
(a false start), the engine rotation must be al- dition is corrected. Do not attempt to jump
lowed to come to a complete stop before at- start the engine with another battery. Starting
tempting to restart the engine. If the starter is with batteries larger than those recommended
engaged while the flywheel is rotating, the can bum out the starter motor.
starter pinion and flywheel ring gear may
clash, resulting in damage to the starter. NOTE: Do not drop the starter or strike the starter
frame. Doing so can damage the ceramic per-
NOTE: If the starter does not crank the engine, shut manent magnets inside the starter frame.
BENDIX DRIVE ELECTRIC STARTER
This subsection covers the operation, troubleshooting, and repair of the Bendix drive permanent
magnet electric starter.
Starter
Starter Frame
— Thru Drive Components
(includes Permanent | 7 Bolts (2) N
Hex Flange Magnets)
Screw (2)
a Dust Cover
| | Stop Nut
re Stop Gear Spacer
= Anti-drift
= Spring
Dust Cover spacer
TT
О
|
|
|
|
/
|
|
|
|
|
Drive Pinion
Start Brushes And 7
arter Brush Springs
Assembly D A
Commutator L— — | с
Drive End Ca
End Cap Armature | o] Р
Figure 8-7. Bendix Drive Electric Starter.
Operation
When power is applied to the starter, the armature ro- the drive shaft, it rotates the flywheel and “cranks” the
tates. As the armature rotates, the drive pinion moves engine.
out on the splined drive shaft and into mesh with the
flywheel ring gear. When the pinion reaches the end of
8.10
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
When the engine starts, the flywheel rotates faster
than the starter armature and drive pinion. This moves
the starter, the armature stops rotating and the drive
pinion is held in the retracted position by the anti-drift
the drive pinion out of mesh with the ring gear and into spring.
the retracted position. When power is removed from
Troubleshooting Guide
Problem Possible Fault Correction
Battery 1. Check the specific gravity of battery. If low, recharge or replace battery as necessary.
Starter ee 1. Clean corroded connections and tighten loose connections.
Does Not Wiring
Energize 2. Replace wires in poor condition and with frayed or broken insulation.
Starter Switch
1. Bypass the switch or solenoid with a jumper cable. If starter cranks normally, replace
Or
Solenoid the faulty components.
Battery 1. Check the specific gravity of battery. 1f low, recharge or replace battery as necessary.
1. Check for excessively dirty or worn brushes and commutator. Clean using a coarse
Starter Brushes cloth (not emery cloth).
Energ izes 2. Replace brushes if excessively or unevenly wom.
¿ lowly 1. Make sure the cluich or transmission is disengaged or placed in neutral. This is es-
Transmission pecially important on equipment with hydrostatic drive. The transmission must be
Or exactly in neutral to prevent resistance which could keep the engine from starting.
Engine 2. Check for seized engine components such as the bearings, connecting rod, and
piston.
Starter Removal And Installation
Refer to the “Disassembly” and “Reassembly” sec-
tions for starter removal and installation procedures.
Starter Drive Service
(Refer To Figure 8-7.)
Every 500 hours of operation (or annually, whichever
occurs first), clean and lubricate the splines on the
starter drive shaft. If the drive pinion is worn, or has
chipped or broken teeth, it must be replaced.
It is not necessary to completely disassemble the
starter to service the drive components. Service the
drive as follows:
1. Remove the starter from the engine.
2. Remove the dust cover.
. Hold the drive pinion in a vice with soft jaws when
removing and installing the stop nut. The armature
will rotate with the nut until the drive pinion stops
against internal spacers.
NOTE: Do not overtighten the vise as this can
distort the drive pinion.
. Remove the stop nut, stop gear spacer, anti-drift
spring, dust cover spacer, and drive pinion.
. Clean the splines on drive shaft thoroughly with
solvent. Dry the splines thoroughly.
. Apply a small amount of Kohler electric starter
drive lubricant to the splines.
NOTE: Kohler electric starter drive lubricant must
be used on all Kohler electric starter
drives. The use of other lubricants can
cause the drive pinion to stick or bind.
8.11
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
7. Apply a small amount of Loctite® no. 271 to the
stop nut threads.
8. Install the drive pinion, dust cover spacer, anti-drift
spring, stop gear spacer, and stop nut. Torque the
stop nut to 17.0/19.2 N-m (135 Ibf-in).
9. Install the dust cover.
Starter Disassembly
1.
Remove the dust cover, stop nut, stop gear spac-
er, anti-drift spring, dust cover spacer, and drive
pinion. Refer to “Starter Drive Service” above.
. Scribe a small line on the drive end cap, opposite
the line on the starter frame. These lines will serve
as match marks when reassembling the starter.
See Figure 8-10.
. Remove the thru bolis.
. Remove the commutator end cap with brushes
and brush springs.
. Remove the drive end cap.
. Remove the armature and thrust washer from in-
side the starter frame.
Brush Replacement
1. Remove the brush springs from the pockets in
brush hoider. See Figure 8-8.
2. Remove the self-tapping screws, negative (-)
brushes, and plastic brush holder.
3. Remove the hex flange nut and fiber washer from
the stud terminal.
Remove the stud terminal with positive (+)
brushes and plastic insulating bushing from the
end cap.
4. Reinstall the insulating bushing to the new stud
terminal with positive (+) brushes. install the stud
terminal with bushing into the commutator end
cap. Secure the stud with the fiber washer and hex
flange screw.
5. Install the brush holder, new negative (-) brushes,
and self-tapping screws.
6. Install the brush springs and brushes into the
pockets in brush holder. Make sure the chamfered
sides of brushes are away from the brush springs.
NOTE: Use a brush holder tool to keep the
brushes in the pockets. A brush holder
tool can easily be made from thin sheet
metal. See Figure 8-9.
Self-Tapping
7 Brush Springs
Screw /
я - >
Negative (-) ;
Brush Brush Holder
Negative (-)
Brush
N U
Stud Terminal With
Positive (+) Brushes
Self-Tapping
Screw
Figure 8-8. Commutator End Cap With Brushes.
Sheet Metal
Brush Holder Tool
| 178"
Brush Holder Tool Installed
Over Brushes And End Cap
Figure 8-9. Brush Holder Tool.
8.12
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Commutator Service
Clean the commutator with a coarse, lint free cloth. Do
not use emery cloth.
If the commutator is badly worn or grooved, tum it
down on a lathe or replace the armature.
Starter Reassembly
1. Place the thrust washer over the drive shaft of ar-
mature.
2. Insert the armature into the starter frame. Make
sure the magnets are closer to the drive shaft end
of armature. The magnets will hold the armature
inside the frame.
3. Install the drive end cap over the drive shaft. Make
sure the match marks on the end cap and starter
frame are aligned. See Figure 8-10.
Match
Marks
Figure 8-10. Starter Assembly Match Marks.
4. Install the brush holder tool to keep the brushes in
the pockets of the commutator end cap.
5. Align the match marks on the commutator end cap
and starter frame. Hold the drive end and commu-
tator end caps firmly to the starter frame. Remove
the brush holder tool.
6. install the thru bolts and tighten securely.
7. Lubricate the drive shaft with Kohler electric starter
drive lubricant. Install the drive pinion, dust cover
spacer, anti-drift spring, stop gear spacer, stop
nut, and dust cover. Refer to “Starter Drive Serv-
ice” above,
"SOLENOID SHIFT ELECTRIC STARTER
This sub-section covers the solenoid shift electric
starter. Much of the information in the preceding sub-
section relates to this starter, therefore it is not re-
peated here. Please use ihe exploded view on the
following page for the disassembly and assembly pro-
cedure.
8.13
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
Frame (Includes
Permanent Magnets)
Plunger
Hex Flange
Screw (2) Spring
Solenoid
And Brush Springs
Commutator
End Cap
Hex Cap
Screw (2).
— Е
| @-— Thrust Washer
| Dust “~ Retainer
С
over Seal
Thu 7
| Bolts (2) Drive Pinion
| >
| Drive Lever
LA
Armature
Figure 8-11. Solenoid Shift Electric Starter
Operation
When power is applied to the starter the electric sole-
noid moves the drive pinion out onto the drive shaft
and into mesh with the flywheel ring gear. When the
pinion reaches the end of the drive shaft it rotates the
flywheel and cranks the engine.
When the engine starts and the start switch is released
the starter solenoid is deactivated, the drive lever
moves back, and the drive pinion moves out of mesh
with the ring gear into the retracted position.
Starter Removal and Installation
Refer {0 the disassembly and reassembly sections for
starter removal and installation procedures.
Starter Disassembly
1. Remove clip.
2. Remove cap screws and solenoid. Scribe align-
ment marks on caps and frame 1o aid assembly.
3. Remove thru bolts, drive end cap, commutator
end cap, and frame.
4. Remove drive (ever.
5. Remove thrust washer and retainer to remove
drive pinion from shaft.
Brush Replacement
Replacing brushes in the solenoid shift starts is ex-
actly the same procedure as explained in the previous
sub-section. Refer to page 8.12, figure 8-8 , figure
8-9.
Commutator Service
Same as previous sub-section.
Starter Service
Clean drive lever and armature shaft. Apply Kohler
electric starter drive lubricant or equivalent to lever
and shaft.
Starter Reassembly
1. Slide frame over armature and place commutator
end cap in position. Hold in position temporarily
with tape.
8.14
SECTION 8
ELECTRICAL SYSTEMS AND COMPONENTS
NOTE: Be sure alignment marks on caps and 4. Place solenoid plunger on drive lever and position
frame are in proper position. drive end cap over drive shaft. (Be sure the rub-
ber dust cover is in place at the drive lever.)
2. Place drive pinion (with seal), thrust washer and 5. Fasten the end caps with the thru bolts.
retainer on drive shat. 6. Place the spring in the solenoid and fasten sole-
noid to drive end cap using hex cap screws.
3. Place lever in position on drive shaft, 7. Replace the clip.
8.15
COMMAND 12.5
SECTION 9
DISASSEMBLY
WARNING: Accidental Starts!
Before servicing the engine or equipment, always disconnect the spark plug lead to
prevent the engine from starting accidentally. Ground the lead to prevent sparks
which could cause fires.
The following sequence is suggested for complete
engine disassembly. This procedure can be varied 10
accommodate options or special equipment.
Clean all parts thoroughly as the engine is disassem-
bled. Only clean parts can be accurately inspected
and gauged for wear or damage. There are many
commercially available cleaners that will quickly re-
move grease, oil, and grime from engine parts. When
such a cleaner is used, follow the manufacturers in-
structions and safety precautions carefully.
Make sure all traces of the cleaner are removed be-
fore the engine is reassembled and placed into opera-
tion. Even small amounts of these cleaners can
quickly break down the lubricating properties of en-
gine oil.
TYPICAL DISASSEMBLY SEQUENCE
Remove spark plug.
Drain oil.
Remove muffler and bracket.
Remove air cleaner cover.
Remove air cleaner element, base, and
breather hose.
Remove choke control.
Remove fuel tank and bracket.
Remove retractable starter.
Remove fuel pump.
10. Remove starter cover — electrical starter.
11. Remove rectifier-regulator.
12. Remove Oil Sentry.
13. Remove throttle control bracket.
SARNA
© N ©
©
14. Remove carburetor.
15. Remove valve cover.
16. Remove cylinder head baffle.
17. Remove blower housing and baffles.
18. Remove ignition module.
19. Remove fuel line.
20. Remove cylinder head push rods/gasket.
21. Remove drive cup, grass screen, flywheel and
fan.
22. Remove stator and wiring harness.
23. Remove oil fill tube — if necessary.
24. Remove closure plate.
25. Remove camshaft and hydraulic lifters.
26. Remove balance shaft.
27. Remove connecting rod.
28. Remove piston.
29. Remove crankshaft.
30. Remove main bearing.
31. Remove governor gear.
32. Remove governor cross shaft seal.
DISCONNECT SPARK PLUG LEAD
NOTE: Pull on boot only, to prevent damage to spark
plug lead.
DRAIN OIL FROM CRANKCASE AND RE-
MOVE OIL FILTER
1. Remove the oil drain plug and oil fill cap/dipstick.
See Figure 9-1.
2. Allow ample time for the oil to drain from the
crankcase and oll filter.
3. Remove and discard the oil filter.
9.1
SECTION 9
DISASSEMBLY
aa
Le
an
=
>
y
PEN
Heu
. - он ea
a VR i dO Et DA
in Plug:
pdr api ren e
E
“ON Dra
REMOVE AIR CLEANER
1. Remove the knob and air cleaner cover. See Fig-
ure 9-4,
Figure 9-1. Removing Oil Drain Plug.
REMOVE MUFFLER
1. Remove the hex flange nuts from exhaust studs
and hex flange screws from muffler bracket. See
Figures 9-2 and 9-3.
2. Remove the muffier and gasket from exhaust out-
{et flange.
y Hex Flange Nut
~~ y
|
|
Muffler Bracket
1 #
Figure 9-4. Removing Air Cleaner Cover.
2. Remove the wing nut, washer, element cover,
element and precleaner. See figure 9-5.
Figure 9-2. Removing Muffler.
Figure 9-3. Removing Muffler.
Air Cleaner Base Element Cover
Fl
Li
- A
Element Cover Wing Nut
4
i
>
Foam Precleaner
An wi
DS
Figure 9-5. Removing Air Cleaner Elements.
3. Remove the hex flange nuts from the intake studs,
and the air cleaner base and gasket from the
studs. See Figure 9-6.
4. Loosen the hose clamp and disconnect the
breather hose from the rocker arm cover. Remove
the air cleaner base from the studs and discon-
nect choke linkage from the carburetor choke le-
ver. See Figure 9-7.
9.2
SECTION 9
DISASSEMBLY
Figure 9-6. Removing Air Cleaner Base.
Breather Hose
X
Choke Linkage
a
Figure 9-7. Removing Air Cleaner Base.
REMOVE FUEL TANK
Explosive Fuel!
A vir Gasoline may be present in the carbu-
retor and fuel system. Gasoline is ex-
tremely flammable, and its vapors can
explode if ignited. Keep sparks, open
— flames, and other sources of ignition
away from the engine.
1. Turn fuel shut-off valve to OFF (horizontal) posi-
tion.
2. Remove hex flange nuts from lower bracket and
hex flange screws from upper bracket of fuel tank.
See Figures 9-8 and 9-9.
3. Remove the fuel tank and disconnect fuel hose
from shut-off valve.
Figure 9-9. Removing Fuel Tank.
REMOVE RETRACTABLE STARTER
1. Remove the five hex flange screws and retractable
starter. See Figure 9-10.
Figure 9-10. Removing Retractable Starter.
9.3
SECTION 9
DISASSEMBLY
REMOVE FUEL PUMP
Explosive Fuel!
ÁN vanas Gasoline may be present in the carbu-
retor and fuel system. Gasoline is ex-
tremely flammable, and it’s vapors can
explode if ignited. Keep sparks, open
— flames, and other sources of ignition
away from the engine.
1. Disconnect the fuel line from the outlet and inlet
fittings of the fuel pump. See Figure 9-11.
2. Remove the two hex flange screws, fuel pump, Figure 89-12. Removing Bendix Drive Starter.
and gasket.
REMOVE RECTIFIER-REGULATOR
1. Remove the wire connector from the rectifier-regu-
lator. See Figure 9-13.
2. Remove the two hex flange screws and rectifier-
regulator.
JR Rectifier-Regulato
/
Hex Flange Screws:
Figure 9-11. Removing Fuel Pump.
REMOVE ELECTRIC STARTER
Electric Starter (Bendix Drive or Solenoid
Shift)
1. Disconnect the lead from the stud terminal. See Figure 9-13. Removing Rectifler-Regulator.
Figure 9-12. Disconnect both leads on Solenoid
Shift Starter. |
REMOVE OIL SENTRY ™
2. Remove the two hex flange screws and starter
cover. 1. Disconnect the lead from the Oil Sentry ™ switch.
3. Remove the starter assembly and spacers from 2. Remove Oil Sentry™ switch from the oil filter
the studs. adapter. See Figure 9-14.
9.4
SECTION 9
DISASSEMBLY
| Throttle Control Bracket _
>
coh e
, A 1
;
‚3
Governor Spring
Figure 9-14. Removing Oil Sentry.
REMOVE THROTTLE CONTROL
BRACKET
1. Remove two hex flange screws from throttle con-
trol bracket. See Figure 8-15.
2. Remove govemor lever spring from throttte control
bracket. See Figure 9-16.
Figure 9-16. Removing Governor Spring.
REMOVE CARBURETOR
Explosive Fuel!
AA warning Gasoline may be present in the carbu-
retor and fuel system. Gasoline is ex-
tremely flammable, and its vapors can
explode if ignited. Keep sparks, open
— flames, and other sources of ignition
ÿ Throttle Control Bracket
Figure 9-15. Removing Throttle Control Bracket.
away from the engine.
1. Remove fuel line from carburetor inlet fitting. See
Figure 9-17.
2. Disconnect the throttle linkage from the bushing in
carburetor governor lever.
3. Remove carburetor and gasket from intake studs.
tia "i
Throttle Linkage
+
anid [1
Carburetorg
La EZ
Figure 9-17. Removing Carburetor.
9.5
SECTION 9
DISASSEMBLY
REMOVE VALVE COVER
1. Remove the five hex flange valve cover screws
and valve cover from the cylinder head assembly.
See Figure 9-18.
NOTE: The valve cover is sealed to the cylinder head
using R1V silcone sealant. When removing
valve cover, use care not to damage the gas-
ket surfaces of cover and cylinder head.
Vaive Cover
Lift Bra et j
Figure 9-18. Removing Valve Cover.
REMOVE CYLINDER HEAD BAFFLE
1. Remove the hex flange screws securing the cylin-
der head baffle to the cylinder head. See Figure
9-19. Remove the baffle.
Tn
À Cylnder Head Batilé
E
Figure 9-19. Removing Cylinder Head Baffle.
REMOVE BLOWER HOUSING AND
BAFFLES
1. Remove the hex flange screws from blower hous-
ing and baffles. Disconnect wire hamess from the
key switch, if equipped. Remove the blower hous-
ing and baffles.
Figure 9-20. Removing Blower Housing and
Baffies.
REMOVE IGNITION MODULE
1. Disconnect the kill lead from the ignition module
terminal. See Figure 9-21.
2. Rotate fiywheel magnet away from ignition mod-
ule.
3. Remove the two hex flange screws and ignition
module.
A N
Figure 9-21. Removing Ignition Module.
REMOVE FUEL LINE
1. Remove the hex flange screw, clip, and fuel line.
See Figure 9-22.
9.6
SECTION 9
DISASSEMBLY
oe = - mr CLP a Fuel Line
| Hex Flange Screw .
mere "os a - e E
a я Ч а
DISASSEMBLE CYLINDER HEAD
1. Remove the spark plug. See Figure 9-25.
Figure 9-22. Removing Fuel Line.
REMOVE CYLINDER HEAD
1. Remove the hex flange screws, spacer (from the
screw by the exhaust port), cylinder head, push
rods, and cylinder head gasket. See Figures 9-23
and 9-24.
Rocker Shaft
DNS
e:
Rocker Arms
Spark Plug
mm Breather Reed Retainer
TS JZ And Breather Reed
a o> \ р x
‘Hex Flangeh
tL. Hex Flange Screw
meva dE MUI And Spacer
Figure 9-23. Removing Cylinder Head.
Cylinder Head
Gasket
Figure 9-24. Removing Cylinder Head Gasket.
Figure 9-25. Removing Spark Plug And
Rocker Arms.
2. Remove the hex flange screw, breather reed re-
tainer, and breather reed.
3. Remove the rocker shaft (from the breather side of
head), and rocker arms.
4. Remove the valves:
a. Compress the valve springs using a valve
spring compressor. See Figure 9-26.
b. Remove the keepers, valve spring caps, vaive
springs, exhaust valve rotator, intake valve
spring seat, and intake valve stem seal. See
Figures 9-27 and 9-28.
5. Remove the two hex cap screws and rocker
bridge.
Valve Spring
Compressor
Figure 9-26. Removing Valves With Valve
Spring Compressor.
9.7
SECTION 9
DISASSEMBLY
Valve
Spring Cap >
‘Keepers
Pi
E
— me Valve Springs
Figure 9-27. Removing Valves.
x lathes Fg, TE
Screw And Drive Cup.
An
‚Hex Cap} 2. Unsnap and remove the grass screen from fan.
Screws
LF
hl
3. Remove the flywheel from the crankshaft using a
puller. See Figure 8-30.
PB Strap Wrench =
po
+ |
a
he
^^ р
L A
y x "ul a nu e N N.
Exhaust pm Intake Valve Intake Valve Flywheel
Valve Rotator Wf Spring Seat Msn Seal no
Figure 9-28. Removing Valves.
REMOVE DRIVE CUP, GRASS SCREEN, Figure 9-30. Removing Flywheel With A Puller.
FLYWHEEL, AND FAN 4. Remove the four hex flange screws and fan from
NOTE: Always use the flywheel strap wrench to hold flywheel. See Figure 9-31.
the flywheel when loosening or tightening the
flywheel and fan retaining fasteners. Do not | Hex Flange
use any iype of bar or wedge between the fins 2 ) Screws (4)
of cooling fan as the fins could become Fan a |
cracked or damaged.
NOTE: Always use a puller to remove the fiywheel
from the crankshaft. Do not strike the crank-
shaft or flywheel, as these parts could be-
come cracked or damaged.
1. Remove the hex flange screw, plain washer, and
drive cup. See Figure 9-29. Figure 9-31. Removing Fan From Fiywheel.
9.8
SECTION 9
DISASSEMBLY
REMOVE THE STATOR AND WIRING
HARNESS
1. Remove the stator leads from connector body.
2. Remove the nex flange screw and clip securing
the stator leads to the crankcase. See Figure
9-32.
3. Remove the hex flange screw and clip securing
the kill lead to the crankcase. Remove the four
hex socket head screws and stator.
Kill LEN
Figure 9-32. Removing Stator.
REMOVE CLOSURE PLATE
1. Remove the twelve hex flange screws securing
the closure plate to the crankcase. See Figure
9-33.
Figure 9-33. Removing Closure Plate.
2. Locate the splitting noiches in the seam of the
closure plate and crankcase. See Figure 9-34. Pry
the closure plate from the crankcase using a large
flat-blade screwdriver.
Figure 9-34. Splitting Notch of Closure Plate/
Crankcase.
NOTE: Insert the screwdriver only in the splitting
notches. Do not pry on the gasket surfaces of
the closure plate or crankcase as this can
cause leaks.
REMOVE OIL PICKUP, OIL PRESSURE
RELIEF VALVE, OIL PUMP, AND OIL SEAL
1. Remove the oi! seal from the closure plate. See
Figure 9-35.
2. Remove the hex flange screw, clip, oil pickup, and
O-ring seal.
O-ring
7
+
E
И
Hex Flange Screw a E à "e
——
Figure 9-35. Removing Oil Seal And Pickup.
3. Remove the hex socket screw, oil pressure relief
bracket, relief valve body, piston, and spring. See
Figures 9-35 and 9-36.
9.9
SECTION 9
DISASSEMBLY
2. Mark or identify the hydraulic lifters as either in-
A d Hex Socket take or exhaust. See Figure 9-39. Remove the
Relief Valve Bracket " Screw
lifters from the crankcase.
Spring NOTE: The intake hydraulic lifter is farthest from
the crankcase gasket surface. The ex-
| haust hydraulic lifter is nearest to the
piston crankcase gasket surface.
||
Valve Body
Figure 9-36. Removing Oil Pressure Relief Valve
Body, Piston, And Spring.
4. Remove the three hex flange screws, oil pump
cover, O-ring, and oil pump rotors. See Figure
9-37.
Pr
Vas
Exhaust Valve
uy
Intake Valve
Lifter
Figure 9-37. Removing Oil Pump.
REMOVE CAMSHAFT
AND HYDRAULIC LIFTERS
1. Remove the camshaft and shim. See Figure 9-38.
Figure 9-39. Identifying Hydraulic Lifters.
REMOVE BALANCE SHAFT
1. Remove the balance shaft from the crankcase.
See Figure 9-40.
BE rs És Balance
у = Shaft
Figure 9-38. Removing Camshaft.
Figure 9-40. Removing Balance Shaft.
REMOVE CONNECTING ROD AND
PISTON
1. Remove the two hex flange screws and connect-
ing rod cap. See Figure 9-41.
9.10
SECTION 9
DISASSEMBLY
NOTE: If a carbon ridge is present at the top of
the bore, use a ridge reamer tool to re-
move it before attempting to remove the
piston.
2. Carefully push the connecting rod and the piston
away from the crankshaft and out of the cylinder
bore.
pg Hex Flange Screws ‘
Figure 9-41. Removing Connecting Rod.
REMOVE PISTON FROM CONNECTING
ROD
1. Remove the wrist pin retainer and wrist pin. Sepa-
rate the piston from the connecting rod. See Fig-
ure 9-42.
MA Piston
Wrist Pin SEES :
Retainer pg §
Connecting
Rod
Figure 9-42. Removing Piston From Connecting
Rod.
REMOVE PISTON RINGS
1. Remove the top and center compression rings
using a ring expander tool. See Figure 8-43.
2. Remove the oil control ring rails, then remove the
rails spacer.
Piston Ring
Expander
Figure 9-43. Removing Piston Rings.
REMOVE CRANKSHAFT
1. Remove the woodruff key from the flywheel taper
end of crankshaft.
2. Remove the crankshaft from the crankcase. See
Figure 9-44.
Crankshaft
Figure 9-44. Removing Crankshaft.
REMOVE FLYWHEEL END OIL SEAL
AND BEARING
1. Remove the oil seal from crankcase.
2. Remove the bearing from the crankcase using
handle #NU-4747 and bearing remover
#KO-1029. See Figure 9-45.
9.11
SECTION 9
DISASSEMBLY
NU-4747 Handle
And KO-1029
( Bearing Remover
Figure 9-45. Removing Crankshaft Bearing.
REMOVE GOVERNOR CROSS SHAFT
AND GOVERNOR GEAR
1. Remove the hitch pin and plain washer from gov-
ernor cross shaft. See Figure 9-46.
2. Remove the cross shaft and plain washer from the
crankcase.
Cross Shaft
Oil Seal
Figure 9-47. Removing Cross Shaft Oil Seal.
4. If necessary, remove the governor gear and regu-
lating pin. See Figure 9-48.
Hitch Pin
Fp * Governor
Cross Shaft
Regulating Ping
E
Governor Gear
3. Remove the governor cross shat oil seal from the
crankcase. See Figure 9-47.
Figure 9-48. Removing Governor Gear.
NOTE: The governor gear is held onto the gover-
nor gear shaft by small moided tabs in the
gear. When the gear is removed from the
shaft these tabs are destroyed. This will
require replacement of the gear; therefore,
remove the gear only if absolutely neces-
sary (such as when reboring, doing major
engine rebuilding, etc.).
9.12
COMMAND 11, 12.5, 14
SECTION 10
INTERNAL COMPONENTS
This section covers the operation, inspection, and repair/reconditioning of major internal engine
components. The following components are not covered in this section. They are covered in sec-
tions of their own:
Air Cleaner, Section 4
Carburetor & External Governor, Section 5
Retractable Starter, Section 7
Ignition, Charging, & Electric Starter, Section 8
Clean all parts thoroughly. Only clean parts can be accurately inspected and gauged for wear or
damage. There are many commercially available cleaners that will quickly remove grease, oil,
and grime from engine parts. When such a cleaner is used, follow the manufacturer's instructions
and safety precautions carefully.
Make sure all traces of the cleaner are removed before the engine is reassembled and placed into
operation. Even smatl amounts of these cleaners can quickly break down the lubricating proper-
ties of engine oil.
Refer to A Guide To Engine Rebuilding (TP-2150) for additional information. Measurement Guide
(TP-2158-A) and Engine Evaluation Record (TP-2096-B) are also available; use these to record
inspection results.
AUTOMATIC COMPRESSION RELEASE compression stroke. The reduced compression re-
(ACR) sults in an effective compression ratio of about 2:1
during cranking.
This engine is equipped with an Automatic Compres-
sion Release (ACR) mechanism. ACR lowers com- After starting, engine speed increases to over 700
pression at cranking speeds to make starting easier. RPM. Centrifugal force moves the lever and the con-
trol pin drops into the recess in the exhaust cam lobe.
When in the recess, the control pin has no effect on
the exhaust valve and the engine operates at full
The ACR mechanism consists of a lever and control power.
pin assembly attached to the gear on the camshaft.
At cranking speeds (700 RPM or lower), the control pin When the engine is stopped, the spring returns the
protrudes above the exhaust cam lobe. This pushes lever and control pin assembly to the compression
the exhaust valve off its seat during the first part of the release position ready for the next start.
Operation
10.1
SECTION 10
INTERNAL COMPONENTS
Benefits
Because of the reduced compression at cranking
speeds, several important benefits are obtained:
1. Manual (retractable) starting is much easier. With-
out ACR, manual starting would be virtually impos-
sible.
2. Electric start models can use a starter and battery
size that are practical for the applications in which
these engines are used.
3. ACR eliminates the need for a spark retard/ad-
vance mechanism. A spark retard/advance
mechanism would be required on engines without
ACR to prevent the “kickback” that would occur
during starting. ACR eliminates this “kickback”
making manual starting safer.
4. The choke control setting is less critical with ACR.
In the event of flooding, excess fuel is blown out
the opened exhaust valve and does not hamper
starting.
5. Engines with ACR start much faster in cold
weather than engines without ACR.
6. Engines with ACR can be started with spark plugs
that are worn or fouled. Engines without ACR
probably could not be started with those same
spark plugs.
CAMSHAFT
Inspection And Service
Inspect the gear teeth of the camshaft. If the teeth are
badly worn, chipped, or some are missing, replace-
ment of the camshaft will be necessary.
CRANKSHAFT
Inspection And Service
Inspect the gear teeth of the crankshaft. If the teeth
are badly worn, chipped, or some are missing, re-
placement of the crankshaft will be necessary.
Inspect the crankshaft bearings for scoring, grooving,
etc. Do not replace bearings unless they show signs
of damage or are out of running clearance specifica-
tions. If the crankshaft turns easily and noiselessly,
and there is no evidence of scoring, grooving, etc., on
the races or bearing surfaces, the bearings can be
reused.
Inspect the crankshaft keyways. If worn or chipped,
replacement of the crankshaft will be necessary.
Inspect the crankpin for score marks or metallic
pickup. Slight score marks can be cleaned with cro-
cus cloth soaked in oil. If wear limits, as stated in
“Specifications and Tolerances” are exceeded, it will
be necessary to either replace the crankshaft or
regrind the crankpin to 0.25 mm (0.010 in) undersize.
If reground, a 0.25 mm (0.010 in) undersize connect-
ing rod (big end) must then be used to achieve proper
running clearance. Measure the crankpin for size, ta-
per, and out-of-round.
NOTE: If the crankpin is reground, visually check to
ensure that the fillet blends smoothly with the
crankpin surface. See Figure 10-1.
High Point From
Fillet Intersections
— + AY
The Fillet Must
Blend Smoothly
With The Bearing
Journal Surface
-_ 45°
Minimum
This Fillet Area
Must Be
Completely Smooth
Figure 10-1. Crankpin Fillets.
NOTE: When grinding a crankshaft, grinding stone
deposits can get caught in oil passages
which could cause severe engine damage.
Remove the sealing plug each time the crank-
shaft is ground to provide easy access for
cleaning any grinding deposits that may col-
lect in the oil passages.
10.2
SECTION 10
INTERNAL COMPONENTS
CRANKCASE
Inspection And Service
Check all gasket surfaces to make sure they are free
of gasket fragments. Gasket surfaces must also be
free of deep scratches or nicks.
Check the cylinder bore wall for scoring. In severe
cases, unburned fuel can cause scuffing and scoring
of the cylinder wall. It washes the necessary lubricat-
ing oils off the piston and cylinder wall. As raw fuel
seeps down the cylinder wail, the piston rings make
metal to metal contact with the wall. Scoring of the
cylinder wall can also be caused by localized hot
spots resulting from blocked cooling fins or from in-
adequate or contaminated lubrication.
If the cylinder bore is badly scored, excessively worn,
tapered, or out of round, resizing is necessary. Use
an inside micrometer to determine amount of wear
(refer to the “Specifications, Tolerances, And Special
Torque Values”, in Section 1), then select the nearest
suitable oversize of either 0.25 mm (0.010 in) or 0.50
mm (0.020 in). Resizing to one of these oversizes
will allow usage of the available oversize piston and
ring assemblies. Initially, resize using a boring bar,
then use the following procedures for honing the cylin-
der.
Honing
While most commercially available cylinder hones can
be used with either portable drills or drill presses, the
use of a low speed drill press is preferred as it facili-
tates more accurate alignment of the bore in relation
to the crankshaft crossbore. Honing is best accom-
plished at a drill speed of about 250 RPM and 60
strokes per minute. After instailing coarse stones in
hone, proceed as follows:
1. Lower hone into bore and after centering, adjust
so that the stones are in contact with the cylinder
wall. Use of a commercial cutting-cooling agent
is recommended.
2. With the lower edge of each stone positioned
even with the lowest edge of the bore, start drill
and honing process. Move the hone up and down
while resizing to prevent the formation of cutting
ridges. Check the size frequently.
NOTE: Measure the piston diameter and resize
the bore to the piston to obtain the speci-
fied running ciearances. Keep in mind the
temperatures caused by honing may
cause inaccurate measurements. Make
sure the bore is cool when measuring.
. When the bore is within 0.064 mm (0.0025 in) of
desired size, remove the coarse stones and re-
place with burnishing stones. Continue with the
burnishing stones until within 0.013 mm (0.0005
in) of desired size and then use finish stones
{220 —280 grit) and polish to final size. A cross-
hatch should be observed if honing is done cor-
rectly. The crosshatch should intersect at approxi-
mately 23 —33° off the horizontal. Too fiat of an
angle could cause the rings to skip and wear ex-
cessively, too steep of an angle will result in high
oil consumption (refer to Figure 10-2).
Figure 10-2. Cylinder Bore Crosshatch
After Honing.
10.3
SECTION 10
INTERNAL COMPONENTS
4. After resizing, check the bore for roundness, taper,
and size. Use an inside micrometer, telescoping
gauge, or bore gauge to take measurements. The
measurements should be taken at three locations
in the cylinder — at the top, middle, and bottom.
Two measurements should be taken (perpendicu-
lar to each other) at each of the three locations.
Measuring Piston-To-Bore Clearance
Before installing the piston into the cylinder bore, it is
necessary that the clearance be accurately checked.
This step is often overlooked, and if the clearances
are not within specifications, engine failure will usually
result.
NOTE: Do not use a feeler gauge to measure pis-
ton-to-bore clearance —it will yield inaccu-
rate measurements. Always use a micro-
meter.
Use the following procedure to accurately measure
the piston-to-bore clearance:
1. Use a micrometer and measure the diameter of
the piston 6 mm (0.24 in) above the bottom of the
piston skirt and perpendicular to the piston pin.
See Figure 10-3.
6 mm (0.24 in.)
Measure 6 mm Above the |
Bottom of Piston Skirt at
Right Angles to Piston Pin
Figure 10-3. Measuring Piston Diameter.
2. Use an inside micrometer, telescoping gauge, or
bore gauge and measure the cylinder bore. Take
the measurement approximately 63.5 mm (2.5 in)
below the top of the bore and perpendicular to the
piston pin.
3. Piston-to-bore clearance is the difference between
the bore diameter and the piston diameter (step 2
minus step 1).
FLYWHEEL
Inspection
Inspect the flywheel for cracks, and the flywheel
keyway for damage. Replace flywheel if cracked.
Replace the fiywheel, the crankshaft, and the key if
flywheel key is sheared or the keyway damaged.
Inspect the ring gear for cracks or damage. Kohler
does not provide ring gears as a serviceable part.
Replace the flywheel if the ring gear is damaged.
CYLINDER HEAD AND VALVES
Inspection And Service
Carefully inspect the valve mechanism parts. inspect
the valve springs and related hardware for excessive
wear or distortion. Check the valves and valve seat
area or inserts for evidence of deep pitting, cracks, or
distortion. Check clearance of the valve stems in
guides. See Figure 10-4 for valve details and specifi-
cations.
10.4
SECTION 10
INTERNAL COMPONENTS
EXHAUST VALVE | A INTAKE VALVE
ma DA — С В А NT an
{57 CT
D / EXHAUST
má | A INSERT
TZ
H— + ——a «—H
+4 N INTAKE
| INSERT
D >
ul
Е T A 5
| A
DIMENSION INTAKE EXHAUST
A Seat Angle 89° 89°
B Insert O.D. 37.987/38.013 34.013/33.987
С Guide Depth 6.5 6.5
D Guide 1.D. 7.033/7.058 7.033/7.058
E Valve Head Diameter 35.63/35.37 31.63/31.37
F Valve Face Angle 45° 45°
G Valve Margin (Min.) 1.5 1.5
H Valve Stem Diameter 6.982/7.000 6.970/6.988
Figure 10-4. Valve Details.
Hard starting, or loss of power accompanied by high
fuel consumption may be symptoms of faulty valves.
Although these symptoms could also be attributed to
worm rings, remove and check the valves first. After
removal, clean the valve heads, faces, and stems with
a power wire brush. Then, carefully inspect each
valve for defects such as warped head, excessive cor-
rosion, or worn stem end. Replace valves found to be
in bad condition. A normal valve and valves in bad
condition are shown in the accompanying illustrations.
10.5
SECTION 10
INTERNAL COMPONENTS
Normal: Even after long hours or operation a valve Leakage: A poor grind on face or seat of valve will
can be reconditioned and reused if the face and mar- allow leakage resulting in a burned valve on one side
gin are in good shape. If a valve is worn to where the only.
margin is less than 1/32 in do not reuse it. The valve
shown was in operation for almost 100 hours under
controlled test conditions.
Bad Condition: The valve depicted here should be Coking: Coking is normal on intake valves and is not
replaced. Note the warped head; margin damaged harmful. If the seat is good, the valve could be reused
and too narrow. These conditions could be attributed after cleaning.
to excessive hours or a combination of poor operating
conditions.
10.6
SECTION 10
INTERNAL COMPONENTS
Carbon Cut: Excessive buildup of deposits in the
combustion chamber may result in valve damage be-
cause deposits can become hard enough to cut the
valve. Cleaning of the cylinder head at proper inter-
vals could prevent such damage.
EEE
Qverheating: An exhaust valve subject to overheating
will have a dark discoloration in the area above the
valve guide. Worn guides and faulty valve springs
may cause this condition. Also check for clogged air
intake, blocked fins, and lean fue] mixture when this
condition is noted.
Stem Corrosion: Moisture in fuel or from condensa-
tion are the most common causes of valve stem corro-
sion. Condensation occurs from improper preserva-
tion during storage and when engine is repeatedly
stopped before it has a chance to reach normal oper-
ating temperatures. Replace corroded valves.
Gum: Gum deposits usually result from using stale
gasoline. This condition is often noted in applications
where fuel is not drained out of tank during the off sea-
son. Gum is a prevalent cause of vaive sticking. The
cure is to ream the valve guides and clean or replace
the valves, depending on their condition.
10.7
SECTION 10
INTERNAL COMPONENTS
Valve Guides
If a valve guide is worn beyond specifications, it will
not guide the valve in a straight line. This may result
in burnt valve faces or seats, loss of compression,
and excessive oil consumption.
To check valve guide to valve stem clearance, thor-
oughly clean the valve guide and, using a split-bali
gauge, measure the inside diameter. Then, using an
outside micrometer, measure the diameter of the valve
stem at several points on the stem where it moves in
the valve guide. Use the largest stem diameter to cal-
culate the clearance. If the clearance exceeds 7.134
mm {0.2809 in) on intake or 7.159 mm (0.2819 in)
on exhaust valve, determine whether the valve stem or
the guide is responsible for the excessive ciearance.
If the valve stem diameter is within specifications, then
recondition the valve guide.
Reconditioning Valve Guide
The valve guides in the cylinder head are not remov-
able. Use a 0.25 mm (0.010 in) O/S reamer. Too! no.
KO-1026.
Valve Seat Inserts
Intake valve seats are usually machined into the cylin-
der head, however, certain applications may specify
hard alloy inserts. The valve seats are not replace-
able. If the seats become badly pitted, cracked, or
distorted, the inserts can be reconditioned.
Use a standard valve seat cutter (see Figure 10-5)
and cut seat to dimensions shown in Figure 10-4.
(Valve details illustration).
Valve Seat
Cutter (Typical) —
Pilot
Figure 10-5. Standard Valve Seat Cutter.
Lapping Valves
Reground or new valves must be lapped in, to provide
fit. Use a hand valve grinder with suction cup for final
lapping. Lightly coat valve face with “fine” grade of
grinding compound, then rotate valve on seat with
grinder. Continue grinding until smooth surface is ob-
tained on seat and on valve face. Thoroughly clean
cylinder head in soap and hot water to remove all
traces of grinding compound. Afier drying cylinder
head, apply a light coating of SAE 10 oil to prevent
rusting.
Intake Valve Stem Seal
These engines use valve stem seals on the intake
valves, Always use a new seal when valves are re-
moved from cylinder head. The seals should also be
replaced if deteriorated or damaged in any way.
Never reuse an old seal.
PISTONS AND RINGS
Inspection
Scuffing and scoring of pistons and cylinder walls oc-
curs when internal temperatures approach the welding
point of the piston. Temperatures high enough to do
this are created by friction, which is usually attributed
to improper lubrication, and/or overheating of the en-
gine.
10.8
SECTION 10
INTERNAL COMPONENTS
Normally, very little wear takes place in the piston
boss-piston pin area. If the original piston and con-
necting rod can be reused after new rings are in-
stalled, the original pin can also be reused but new
piston pin retainers are required. The piston pin is
included as part of the piston assembly —if the pin
boss in piston or the pin, are worn or damaged, a new
piston assembly is required.
Ring failure is usually indicated by excessive oil con-
sumption and blue exhaust smoke. When rings fail,
oll is allowed to enter the combustion chamber where
it 1s burned along with the fuel. High oil consumption
can also occur when the piston ring end gap is incor-
rect because the ring cannot properly conform to the
cylinder wal! under this condition. Oil control is also
lost when ring gaps are not staggered during installa-
tion.
When cylinder temperatures get too high, lacquer and
varnish coliect on pistons causing rings to stick which
results in rapid wear. A worn ring usually takes on a
shiny or bright appearance.
Scratches on rings and pistons are caused by abra-
sive material such as carbon, dirt, or pieces of hard
metal.
Detonation damage occurs when a portion of the fuel
charge ignites spontaneously from heat and pressure
shortly after ignition. This creates two flame fronts
which meet and explode to create extreme hammering
pressures on a specific area of the piston. Detonation
generally occurs from using fuels with too low of an
octane rating.
Preignition or ignition of the fuel charge before the
timed spark can cause damage similar to detonation.
Preignition damage is often more severe than detona-
tion damage — often a hole is quickly bumed right
through the piston dome. Preignition is caused by a
hot spot in the combustion chamber from sources
such as: glowing carbon deposits, blocked fins, im-
properly seated valve, or wrong spark plug.
See Figure 10-6 for some common types of piston
and ring damage.
10.9
SECTION 10
INTERNAL COMPONENTS
Stuck, Broken Rings
Abrasive Scratched Rings
Abrasive Worn Rings
Scored Piston And Rings
Figure 10-6. Common Types Of Piston And Ring Damage.
Replacement pistons are available in STD bore size,
and in 0.25 mm (0.010 in), and 0.50 mm (0.20 in)
oversizes. Replacement pistons include new piston
ring sets and new piston pins.
Service replacement piston ring sets are also avail-
able separately for STD, 0.25 mm (0.010 in), and
0.50 mm {0.020 in), oversized pistons. Always use
new piston rings when installing pistons. Never
reuse old rings.
The cylinder bore must be deglazed before service
ring sets are used.
Some important points to remember when servicing
piston rings:
10.10
SECTION 10
INTERNAL COMPONENTS
1. If the cylinder bore does not need reboring and if
the old piston is within wear limits and free of
score or scuff marks, the old piston may be
reused.
2. Remove old rings and clean up grooves. Never
reuse old rings.
3. Before installing the rings on piston, place the top
two rings, each in turn, in its running area in cylin-
der bore and check end gap (see Figure 10-7).
This gap should be 0.75 mm (0.030 in) max. in a
used cylinder bore and 0.3/0.5 mm (0.012/0.020
in) in a new cylinder bore.
4. After installing the new compression (top and mid-
dle) rings on piston, check piston-to-ring side
clearance. Maximum recommended side clear-
ance is 0.040/0.105 mm (0.0016/
0.0041 in). If side clearance is greater than
specified, a new piston must be used. Referto
Figure 10-8.
7
À
PAN ZN , `
x
x
3 X
\ Y
\
4 I
1
~ !
-
x —
r
0
a Da
а "e
i e
cal PE; a ">
Figure 10-7. Measuring Piston Ring End Gap.
| a Mas й
Figure 10-8. Measuring Piston Ring
Side Clearance.
Install Piston Rings
To install piston rings, proceed as follows:
NOTE: Rings must be installed correctly. Ring
installation instructions are usually in-
cluded with new ring sets. Follow instruc-
tions carefully. Use a piston ring ex-
pander to install rings. Install the bottom
(oil control) ring first and the top compres-
sion ring last. Refer to Figure 10-9.
10.11
SECTION 10
INTERNAL COMPONENTS
Piston Ring
N
Dykem
End Gap Stripe
Ds
NT
“Pip” Mark
Piston
Top Compression Ring
| Center Compression Ring
Oil Control Ring
(Three-piece
Р Expander
Figure 10-9. Piston Ring Installation.
1. Qil Control Ring (Bottom Groove): install the ex-
pander and then the rails. Make sure the ends of
expander are not overlapped.
2. Compression Ring (Center Groove): Install the
center ring using a piston ring installation tool.
Make sure the “pip” mark is up and the PINK
dykem stripe is to the left of end gap.
3. Compression Ring (Top Groove): Install the top
ring using a piston ring installation tool. Make
sure the “pip” mark is up and the BLUE dykem
stripe is to the left of end gap.
CONNECTING RODS
Offset Stepped-cap Connecting Rods are used in all
these engines.
Inspection And Service
Check bearing area (big end) for excessive wear,
score marks, running and side clearances (Refer to
Section 1, “Specifications, Tolerances, And Special
Torque Values”). Replace rod and cap if scored or
excessively worn.
Service replacement connecting rods are available in
STD crankpin size and 0.25 mm (0.010 in) undersize.
The 0.25 mm (0.010 in) undersized rod can be identi-
fied by the drilled hole located in the lower end of the
rod shank. Always refer to the appropriate parts infor-
mation to ensure that correct replacements are used.
OIL PUMP
Inspection And Service
Pump can be checked/replaced without removing clo-
sure plate.
Check oil pressure relief valve body, piston, and
spring — (refer to Figure 10-10). Piston and body
should be free of nicks or burrs. Check spring for
wear or distortion. Spring free length should be ap-
proximately 0.892 in. Replace spring if distorted or
worn.
10.12
SECTION 10
INTERNAL COMPONENTS
Hex Socket
у Screw
Relief Valve Bracket
Valve Body
Figure 10-10. Oil Pressure Relief Valve.
GOVERNOR GEAR
Inspection
inspect the governor gear teeth. Look for any evi-
dence of worn, chipped, or cracked teeth. If one or
more of these problems is noted, replace the govemor
gear.
The governor gear must be replaced once it is re-
moved from the engine.
10.13
COMMAND 11, 12.5, 14
SECTION 11
REASSEMBLY
The following sequence is suggested for complete
engine reassembly. This procedure assumes that all
components are new or have been reconditioned, and
all component subassembly work has been com-
pleted. This procedure may be varied to accommo-
date options or special equipment.
NOTE: Make sure the engine is assembled using all
specified torque values, tightening se-
quences, and clearances. Failure to observe
specifications could cause severe engine
wear or damage.
Always use new gaskets.
TYPICAL REASSEMBLY SEQUENCE
1. Install flywheel end bearing.
Install governor gear and crosshaft.
Install crankshaft.
Install piston rings.
Install piston to connecting rod.
Install piston and rod to crankshaft.
Install balance shaft.
Install hydraulic lifters and camshaft.
9. Check camshaft end play.
10. Install and torque closure plate.
11. (Install oil pump.
12. Install pro end oil seal.
13. Install flywheel end oil seal.
14. Install stator and leads.
15. Install flywheel, grass screen and drive cup.
16. Install fuel line.
17. Install and adjust ignition module,
18. Assemble cylinder head.
19. Instail cylinder head.
20. Install baffles and blower housing.
о мч ол А ом
21. Install cylinder head baffle.
22. install valve cover.
23. Install fuel pump.
24. install electric starter and cover.
25. Install fuel tank.
26. Install rectifier-regulator.
27. install carburetor.
28. Install and adjust governor arm.
29. Install throttle bracket.
30. Install choke and air cleaner base plate.
31. Install air cleaner eiement/precleaner and cover.
32. Install oil filter and Oil Sentry.
33. Install dipstick.
34. Install retractable starter.
35. Install muffier and bracket.
INSTALL FLYWHEEL END BEARING
1. Mark the position of one of the crankcase bearing
oll galleries on the crankcase. See Figure 11-1.
» » |
Make Mark
- e
ë >
—— °
Figure 11-1. Marking Position Of Oil Gallery.
2. Assembie the KO-1028 bearing installer to the
NU-4747 handle. Install the sleeve bearing to the
bearing installer. Align the oil hole in the bearing
with the alignment notch on the installer.
SECTION 11
REASSEMBLY
3. Position the installer/bearing to the bearing bore
of crankcase. Make sure the alignment notch of
installer and mark on crankcase are aligned.
4. Drive the bearing info the crankcase. Make sure
the bearing is installed straight and true in bore
and that the tool bottoms against the crankcase.
NOTE: Make sure the hole in the sleeve bearing
is aligned with the oil gallery in crank-
case. Improper positioning of the bear-
ings can cause engine failure due to lack
of lubrication.
INSTALL GOVERNOR GEAR
AND CROSS SHAFT
NOTE: Reuse of an old (removed) governor gear is
not recommended,
1. Install the thrust washer to governor gear shaft.
2. Position the regulating pin to governor gear/fly-
weights as shown in Figure 11-2. Slide the gover-
nor gear/regulating pin over the governor gear
shaft.
Installe
er
'KO-1030 Seal
ane ees
nETerar ear
Figure 11-3. Cross Shaft Oil Seal.
4. Install one plain washer to the cross shaft and In-
sert the cross shaft (from inside crankcase)
through the crankcase and oil seal. See Figure
11-4.
5. Install one plain washer and hitch pin.
Regulating Pin
Governor
Plain Washer
Hitch Pin
Governor
Cross Shaft
all.
Figure 11-2. Installing Governor Gear.
3. Using the KO-1030 oil seal installer, install a
new governor cross shaft oil seal into the crank-
case. See Figure 11-3.
Figure 11-4. Installing Cross Shaft.
INSTALL CRANKSHAFT
1. Lubricate the fiywheel end bearing surfaces of the
crankshaft and crankcase with engine oil.
2. Insert the crankshaft through the flywheel end
bearing. See Figure 11-5.
SECTION 11
REASSEMBLY
Crankshaft
1. Stagger the piston rings in the grooves until the
end gaps are 120° apart.
2. lubricate the cylinder bore, piston, and rings with
engine oil. Compress the piston rings using a pis-
ton ring compressor. See Figure 11-7.
Figure 11-5. Installing Crankshaft.
INSTALL PISTON RINGS
NOTE: For detailed piston inspection procedures and
piston ring installation procedure refer to the
Section 10— “Internal Components.”
INSTALL PISTON TO CONNECTING ROD
1. Install the piston, connecting rod, piston pin, and
piston pin retainers. See Figure 11-6.
) | Piston
Wrist Pin Ml 7
Retainer 4% )
Connecting
Figure 11-6. Installing Piston To
Connecting Rod.
INSTALL PISTON AND CONNECTING
ROD
NOTE: Proper orientation of the piston/connecting
rod inside the engine is extremely important.
Improper orientation can cause extensive
wear or damage.
sei
LOT st,
Piston Ring Compressor у
Instalied Around Piston == *
x A E a В
м PE #4
+ d N в dE
a ai & "ДЕ
Figure 11-7. Installing Piston And
Connecting Rod.
3. Orient the “Fly” mark on piston towards the fly-
wheel side of crankcase. See Figure 11-8. Gently
push the piston/connecting rod into bore. Do not
pound on the piston.
SECTION 11
REASSEMBLY
. Arrow Must Point
Eo - Towards Fiywheel
E ME.
я
:
=
3 :
. : i 3
. ‚
; +
4, -
. ; ;
Le . =>
= m !
4 +
> ‘
3 o a rr A 2 .
. er ana jl O ES a VE a
. a N PT а ay ый LT. él,
Figure 11-8. Piston Installation Identifier.
4. Lubricate the crankshaft journal and connecting
rod bearing surfaces with engine oil. Install the rod
cap to connecting rod.
5. Install the hex flange screws and torque in incre-
ments to 22.6 N.m (200 ibf-in). See Figure 11-9.
6. Rotate the crankshaft until the piston is at the top
dead center in the cylinder bore.
+ Hex Flange Screws - Po |
CNT EE ето лен еее ав
Figure 11-9. Installing Connecting
Rod Fasteners.
INSTALL BALANCE SHAFT
1. Lubricate the balance shaft bearing surfaces of
crankcase and balance shaft with engine oil.
2. Align the timing mark on the balance shaft gear
and the larger gear on crankshaft. Lower the bal-
ance shaft into the bearing surface in the crank-
case.
Make sure the balance shaft gear, large crankshaft
gear and the governor gear teeth mesh and the
timing marks are aligned. See Figure 11-10.
Crankshaft Timing Mark jy \
(Large Crankgear)
Balance Shaft
Timing Mark
am a MA
Figure 11-10. Aligning Timing Marks On
Crankgear and Balance Shaft Gear.
INSTALL HYDRAULIC LIFTERS
AND CAMSHAFT
1. Lubricate the hydraulic lifters and lifter bores in
crankcase with engine oil.
2. Install the hydraulic lifters into the appropriate in-
take or exhaust lifter bore in the crankcase. See
Figure 11-11.
NOTE: Install the lifters from inside the crank-
case. The chamfered edge of the lifter
must be inserted towards the cylinder
head gasket surface. The intake hydraulic
lifter is farthest from the crankcase gasket
surface. The exhaust hydraulic lifter is
nearest to the crankcase gasket surface.
11.4
SECTION 11
REASSEMBLY
Fan.
Exhaust Valve
Lifter =
mé"
“>
intake Valve | < /
Figure 11-11. Installing Hydraulic Lifters.
3. Lubricate the camshaft bearing surfaces of crank-
case and camshaft with engine oil.
4. Align the timing marks on the camshaft gear and
the smaller gear on crankshaft. Lower the cam-
shaft into the bearing surface in crankcase.
Make sure the camshaft gear and smaller gear on
crankshaft mesh and the timing marks are aligned.
See Figure 11-12.
$ , Crankshaft Timing Mark
(Small Crankgear)
Camshaft
Timing Mark’
‘ .
> e
3
==
В
>
Figure 11-12. Aligning Timing Marks On Crankgear
And Camgear.
Determine Camshaft End Play
1. install the shim spacer, removed during disassem-
bly, to the camshatt.
2. Install the camshaft end play checking tool no.
KO-1031 to the crankcase and camshaft. Secure
the tool to the crankcase with the hex flange
screws provided. See Figure 11-13.
3. Using a flat feeler gauge, measure the camshaft
end play between the shim spacer and the end
play checking tool.
Camshaft end play should be 0.076/0.127 mm
(0.003/0.005 in).
iI.
Shim Spacer
Hex Flange
Flat Feeler
Gauge
Checking Tool &
91001 J N
Figure 11-13. Checking Camshaft End Play.
4. If the camshaft end play is not within the specified
range, remove ihe end play checking tool and
add, remove, or replace shims as necessary.
Several color coded shims are available:
White: 0.69215/0.73025 mm (0.02725/0.02875 in)
Blue: 0.74295/0.78105 mm (0.02925/0.03075 in)
Red: 0.79375/0.83185 mm (0.03125/0.03275 in)
Yellow: 0.84455/0.88265 mm (0.03325/0.03475 in)
Green: 0.89535/0.99345 mm (0.03525/0.03675 in)
Gray: 0.94615/0.98425 mm (0.03725/0.03875 in)
Black: 0.99695/1.03505 mm (0.03925/0.04075 in)
5. Reinstall the end play checking tool and recheck
end play.
6. Repeat steps 4 and 5 until the end play is within
the specified range.
INSTALL OIL PRESSURE RELIEF
VALVE AND OIL PICKUP
Oil Pressure Relief Valve
1. Place the relief valve body in the cavity of the
closure plate.
2. Insert the piston and spring into the body. See
Figure 11-14.
11.5
SECTION 11
REASSEMBLY
3. Install the bracket and hex flange screw. See Fig-
ures 11-14 and 11-15.
fs E Hex Socket
. 7 E Screw
Oil Pressure Relief. »
Valve Bracket
Spring
| piston
*— Relief Valve Body
Figure 11-14. Installing Oil Pressure Relief Valve
Body, Plunger, And Spring.
Oil Pickup
1. Install the oil pickup, O-ring, clip, and hex flange
screw. See Figure 11-15.
NOTE: Lightly grease O-ring and install before oil
PICKUP.
Figure 11-15. Installing Oit Pickup Components.
INSTALL CLOSURE PLATE TO
CRANKCASE
RTV silicone sealant is used as a gasket between the
closure plate and crankcase. GE Silmate ” type
RTV-1473 or RTV-108 silicone sealant (or equiva-
lent) is recommended.
NOTE: Always use fresh sealant. Using outdated
sealant can result in leakage. Refer to Section
2 — “Special Tools” for information on the 52
597 01 silicone sealant dispenser.
1. Prepare the sealing surfaces of the crankcase and
closure plate as directed by the sealant manufac-
turer.
NOTE: Do not scrape the surfaces when cleaning
as this will damage the surfaces. This
could result in leaks. The use of a gasket
removing solvent is recommended.
2. Apply a 1/16” bead of sealant to the closure plate
as shown in Figure 11-16.
Figure 11-16. Closure Plate Sealant Pattern.
3. Install the closure plate to the crankcase and in-
stall the twelve hex flange screws. Tighten the
screws hand tight.
4. Torque the fasteners, in the sequence shown in
Figure 11-17 to 24.4 N-m (216 Ibf-in).
11.6
SECTION 11
REASSEMBLY
Figure 11-18. Installing Oil Pump Gears
And O-ring.
Oil Pump Cover Wg
Figure 11-17. Closure Plate Fastener Torque
Pattern.
INSTALL OIL PUMP
1. Lubricate the oil pump cavity and oil pump rotors
with engine oil. Install the outer and inner oil pump
rotors. See Figure 11-18.
a
2. Install the O-ring in the groove in the closure plate.
Figure 11-19. Installing Oil Pump Cover.
3. Install the cil pump cover (machined side towards
O-ring). Secure with three hex flange screws. See
NOTE: Apply sealant to the oil pump cover hex 1. Slide the seal protector sleeve, no. KO-1037,
flange screws to prevent leakage. over the crankshaft. Generously lubricate the lips
of oil seal with light grease. Slide the oil seal over
Torque the screws as follows: the sleeve.
First Time Installation On A New Closure Plate:
6.2 N-m (55 Ibf-in). 2. Use handle no. KO-1036 and seal driver no.
KO-1027. Install the seals until the driver bottoms
Reinstallation On A Used Closure Plate: 4.0 N-m against the crankcase or closure plate. See Figure
(35 Ibf-in). 11-20.
SECTION 11
REASSEMBLY
Figure 11-20. Installing Oil Seals.
INSTALL STATOR AND WIRING
HARNESS
1. Position the stator leads towards the hole in the
crankcase. Insert the stator leads through the hole
to the outside of the crankcase. See Figure 11-21.
2. Install the stator using four hex socket head
screws.
Torque the screws to 4.0 N-m (35 lbf-in).
3. Secure the stator leads to the crankcase with the
clip and hex flange screw.
4. Install the connector body to the stator leads.
5. Secure the kill lead to the crankcase with the clip
and hex flange screw.
Pe
[Hex Flange Screw & Clip
En es LT “т
tator Lead +
FEES
SEE
Figure 11-21. Installing Stator.
INSTALL FAN AND FLYWHEEL
WARNING: Damaging Crankshaft And Flywheel
A Can Cause Personal Injury!
Using improper procedures to install
the flywheel can crack or damage the
crankshaft and/or flywheel. This not only
causes extensive engine damage, but
can also cause personal injury, since
broken fragments could be thrown from
the engine. Always observe and use the
following precautions and procedures
when installing the flywheel.
NOTE: Before installing the flywheel make sure the
crankshaft taper and flywheel hub are clean,
dry and completely free of lubricants. The
presence of lubricants can cause the flywheel
to be over-stressed and damaged when the
flange screw is torqued to specification.
NOTE: Make sure the flywheel key is installed prop-
erly in the keyway. The flywheel can become
cracked or damaged if the key is not installed
properly in the keyway.
NOTE: Always use a flywheel strap wrench to hold
the flywheel when tightening the fiywheel fas-
tener. Do not use any type of bar wedge be-
tween the cooling fins or flywheel ring gear, as
these parts could become cracked or dam-
aged.
1. Install the tan, spacers and hex flange screws to
the flywheel. See Figure 11-22.
Torque the hex flange screws 10 8.9 N.m (88
ibf-in).
11.8
SECTION 11
REASSEMBLY
Hex Flange
Screws (4)
Fan
Figure 11-22. installing Fan To Fiywheel.
2. Install the woodruff key into the keyway in the
crankshaft.
3. Place the flywheel over the keyway/crankshaft.
Install grass screen, drive cup, plain washer (flat
side of plain washer towards the drive cup), and
the hex flange screw. See Figure 11-23.
4. Hold the flywheel with a strap wrench and torque
the hex flange screw to 66.4 N.m (491 Ibf-in).
Fuel Line,
ur
Figure 11-24. Installing Fuel Line.
INSTALL IGNITION MODULE
1. Instalt the ignition module and hex flange screws
to the bosses on crankcase. Move the module as
far from the flywheel/magnet as possible. Tighten
the hex flange screws slightly.
2. Insert a 10 mm {0.394 in) flat feeler gauge or
shim stock between the magnet and ignition mod-
ule. See Figure 11-25.
Loosen the hex flange screws so the magnet pulls
the module against the feeler gauge.
quen Y
po
a i A. A отт Ча, Re. 8 й
MARS Flat Feeter Gauge:
Figure 11-23. Installing Flywheel.
INSTALL FUEL LINE
1. Install the fuel line, clamp and hex flange screw.
See Figure 11-24.
Figure 11-25. Installing Ignition Module.
3. Tighten the hex flange screws as follows:
First Time Installation On A New Short Block: 6.2
N-m (55 Ibf-in).
All Reinstallations: 4.0 N.m (35 Ibf-in).
4. Rotate the flywheel back and forth; check to make
sure the magnet does not strike the module.
11.9
SECTION 11
REASSEMBLY
Check the gap with feeler gauge and readjust if
necessary. Ney Cap Rocker
. PND ÿ Bridge |
Final Air Gap: 0.203/0.305 mm (0.008/0.012 in). *
“ч
5. Connect the kill lead to the tab terminal on ignition E e kh .
module. Y ho MA.
RS) |
Exhaust intake Valve _ Intake Valve
REASSEMBLE CYLINDER ÿ Valve Rotator * € Spring Seat N Stem Seal
HEAD COMPONENTS —— — —
Figure 11-26. Installing Rocker Bridge
See Figures 11-26, 11-27, 11-28, and 11-29. And Valves.
Valve Spring
1. Install the rocker bridge to the cylinder head. Compressor
Make sure the small (counterbored) hole is to-
wards the exhaust port side of the cylinder head.
Secure the rocker bridge with two hex cap screws. | | и
2. install the intake valve stem seal, intake valve,
intake valve spring seat, intake valve spring, and
valve spring cap. Compress the valve spring us- Figure 11-27. Compressing Valve Springs.
ing a valve spring compressor and install the
Keepers. | Valv e
'Keepers” Spring Cap -—
3. Install the exhaust valve, exhaust valve rotator, de a Le ' |
valve spring, and valve spring cap. Compress the
valve spring using a valve spring compressor and
install the keepers.
4. Position the rocker arms over the valve stems and
rocker arm bridge. Insert the pin (from breather
reed side) through the rocker bridge and rocker
arms. Figure 11-28. Installing Valve Keepers.
11.10
SECTION 11
REASSEMBLY
Rocker Shaft
Figure 11-31. Cylinder Head Fastener
Figure 11-29. Installing Rocker Arms.
Tightening Sequence.
4. Install the spark plug into the cylinder head.
INSTALL CYLINDER HEAD Torque the spark plug to 38.0/43.4 N.m (28/32
Ibf-ft).
1. Install a new cylinder head gasket.
$ У
2. Install the cylinder head spacer (closest to the ; A
exhaust port) and hex flange screws. See Figure Rocker Arms |
Compress Valve
Spring
11-30.
Push Rods
Torque the screws in increments of 10 Ibf+»ft in the
sequence shown in Figure 11-31 to 40.7 N-m (30 x
Ibf-in). |
&
em Figure 11-32. Installing Push Rods
Breather Reed Retainer Under Rocker Arms.
Hex Flange/ 7777 And Breather Reed
‘ м 211i KV” MU 5. Install the breather reed, breather reed retainer,
and hex flange screw.
| E
й
INSTALL BAFFLES AND BLOWER
HOUSING
NOTE: Leave all hardware slightly ioose until all
( в” Hex Flange Screw sheet metal pieces are in position.
gL And Spacer
Tl 1. Install the heat deflector, intake manifold, and gas-
Figure 11-30. Installing Cylinder Head. kets to the cylinder head intake port using two hex
socket screws.
3. Install the push rods and compress the valve
springs. Snap the push rods underneath the rocker Torque the hex socket screws to 9.9 N-m (88
arms. See Figure 11-32. Ibf.in).
11.11
SECTION 11
REASSEMBLY
2. Install the grommet around the high tension lead.
Insert the grommet into the slot in the blower
housing. install the blower housing and baffles
using hex flange screws. See Figure 11-33.
Figure 11-33. Installing Blower
Housing And Baffles.
3. Install cylinder head baffle to the cylinder head
using hex flange screws.
4. Tighten all hardware.
INSTALL VALVE COVER
AND MUFFLER BRACKET
RTV silicone sealant is used as a gasket between the
valve cover and crankcase. GE Silmate™ type
RTV-1473 or RTV-108 silicone sealant (or equiva-
lent) is recommended.
NOTE: Always use fresh sealant. Using outdated
sealant can resull in leakage. Refer to Sec-
tion 2 — “Special Tools” for information on the
52 597 01 silicone sealant dispenser.
1. Prepare the sealing surfaces of the cylinder head
and valve cover as directed by the sealant manu-
tacturer.
NOTE: Do not scrape surfaces when cleaning as
this will damage the surface and could
cause leaks. The use of a gasket remov-
ing solvent is recommended.
2. Apply a 1/16” bead of sealant to the cylinder head
as shown in Figure 11-34.
Figure 11-34. Valve Cover Sealant Pattern.
3. Install the valve cover, lift bracket (lifting hole to-
wards flywheel), and two hex flange screws. In-
stall the remaining hex flange screws. See Figure
11-35.
Valve Cover
ea
is
Figure 11-35. Installing Valve Cover.
4. Torque the screws in the sequence shown in Fig-
ure 11-36, as follows:
First Time Installation On A New Cylinder Head:
10.7 N-m (95 Ibf.in).
All Reinstallations: 7.3 N.m (65 Ibf.in).
11.12
SECTION 11
REASSEMBLY
Figure 11-36. Valve Cover Torque Sequence.
INSTALL FUEL PUMP
1. Install the rubber line and two hose clamps to the
fuel pump end of the metal fuel line. Secure the
rubber fuel line to the steel fuel line with one of the
clamps. See Figure 11-37.
2. Install the gasket, fuel pump, and two hex flange
screws. Jorgue the screws as follows:
First Time installation On A New Short Block: 9.0
N.m (80 Ibf-in).
All Reinstallations: 7.3 N-m (65 Ibf-in).
3. Install the opposite end of the rubber line to the
outlet fitting of the fuel pump. Secure the fuel line
to the outlet fitting with the other hose clamp.
E MES SE CNE E ай 9
ee 4 ©
EIA
Hex Flange Screws:
Figure 11-37. Installing Fuel Pump.
INSTALL ELECTRIC STARTER
Electric Starter (Bendix Drive or Solenoid
Shift)
1. Install the starter and spacers on the mounting
studs. See Figure 11-38.
2. Install the starter cover and the two hex flange
screws.
3. Connect the lead to the starter terminal(s).
NE Starter Cover 8 Spacers Ш
A “a
НН
В
arter
Figure 11-38. Installing Electric Starter.
INSTALL FUEL TANK
1. Connect the fuel hose to the shut-off valve.
11.13
SECTION 11
REASSEMBLY
2. Install hex flange screws 10 upper bracket of fuel
tank. Install hex flange nuts to studs in lower
bracket of fuel tank. See Figures 11-39 and
11-40.
Fuel Tank Bracket :
Figure 11-40. Installing Fuel Tank.
INSTALL RECTIFIER-REGULATOR
1. Install the rectifier-regulator and hex flange
screws. See Figure 11-41.
2. Install the connector to the rectifier-regutator.
Hex Flange Screws.
Connector
Rectifier-Regulator”
Figure 11-41. Installing Recifier-Regulator.
INSTALL CARBURETOR AND EXTERNAL
GOVERNOR COMPONENTS
1. Install the rubber fuel line and two hose clamps to
the metal fuel line. Secure the rubber fuel line to
the metal fuel line with one of the hose clamps.
See Fiqure 11-42.
Throttle Linkage co omo Gasket WEN
Bushing Ma
£
a *
TE A f
ge ca i
r Carburetor
‘ Fuel Line ==
Figure 11-42. installing Carburetor And
External Governor Components.
2. install the bushing and the throttle linkage to the
carburetor throttle lever.
11.14
SECTION 11
REASSEMBLY
3. Install the gasket and carburetor over the intake
studs. Install the free end of the rubber fuel line to
the carburetor fuel inlet fitting as the carburetor is
inserted over the studs. Secure the fuel line with
the other hose clamp.
4. Install the throttle linkage and bushing to governor
lever.
5. Install the govemnor lever to governor cross shaft.
Do not tighten the hex nut on the governor lever
until the lever is adjusted (step 6).
6. Adjust the governor lever/governor gear. See Fig-
ure 11-43.
a. Pull the governor lever away from the carbu-
retor (wide open throttle).
b. Insert a nail in the cross shaft hole or grasp
the cross shaft with a pliers and turn the shaft
counterclockwise as far as it will go.
c. Tighten the hex nut securely.
$ Throttle Bracket
Y § |
Figure 11-44. Instailing Throttie Bracket.
2. Install the govemor spring in the appropriate hole
in the governor arm and throttle control lever, as
indicated in the chart. Note that hole positions are
counted from the top of the lever.
RPM should be checked with a tachometer.
HIGH IDLE | GOV. LEVER {| THROTTLE LEVER
RPM HOLE $ HOLE #
3800 6 3
3600 5 1
3400 4 1
3200 3 1
3000 2 1
7
Hex Nut
Cross Shaft
En. tia
y
E:
De
®
Figure 11-43. Adjusting Governor Lever.
INSTALL THROTTLE BRACKET
1. Install the throttle bracket assembly with two hex
flange screws. See Figures 11-44.
и | | К | Governor Spring
Figure 11-45. Installing Governor Spring.
INSTALL AIR CLEANER
1. Connect choke linkage to the carburetor choke
lever. Install the base plate to the studs and con-
nect the breather hose to the rocker arm cover.
See Figure 11-46.
11.15
SECTION 11
REASSEMBLY
iE
Er
Figure 11-46. Installing Air Cleaner Base Plate.
2. Install the air cleaner base and gasket to the studs
and torque the hex flange nuts to 8.9 N-m (88
ibf-in). See Figure 11-47.
Figure 11-47. Installing Air Cleaner Base Plate.
3. Install the element and precleaner, element cov-
er, washer, and wing nut. See figure 11-48.
Air Cleaner Base = Paper Element
Foam Precleaner
Element Cover JF —— er
Figure 11-48. Installing Air Cleaner Elements.
4. Install the air cleaner cover and knob. See Figure
11-49.
Pree
Air Cleaner Cover
I у, у es |
a 5 A
Figure 11-49. Installing Air Cleaner Cover.
INSTALL RETRACTABLE STARTER
1. Install the retracable starter and five hex flange
screws to biower housing. Leave the screws
slightly loose.
2. Pull the starter handle out untit the pawls engage
in the drive cup. Hold the handle in this position
and tighten the screws securely. See Figure
11-50.
Figure 11-50. Installing Retractable Starter.
INSTALL MUFFLER
1. Install the gasket, muffler, and hex flange nuts to
the exhaust port studs. Leave the nuts slightly
loose, See Figure 11-51.
2. Secure the muffler to the muffler bracket using the
two hex flange screws. See Figure 11-52.
11.16
SECTION 11
REASSEMBLY
3. Torque the hex flange nuts to 24.4 N-m (216
Ibf-in), screws tc 9.9 N-m (88 Ibf-in).
ot
Hex Fiange Nut
Figure 11-51. Installing Muffler.
Figure 11-52. Installing Muffler.
11.17
FOR SALES AND SERVICE INFORMATICN
IN U.S. AND CANADA, CALL
1-800-544-2444
POR TE
Ts НР
Корр ООВ
Кок:
ISSUED: 6/90
KOHLERSNOIMES ===
REVISED: 7/91
ENGINE DIVISION, KOHLER CO, KOHLER, WISCONSIN 53044 LITHO IN U.S.A.
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