927-0752 Onan MCCK
Service
Manual
Engine
927-0752
RCCK SPEC A
WCCK Spec A-H
5-a4
Prinled in U.S.A.
Safety Precautions
It is recornmended that you read your engine manual and become thoroughly acquainted with your equipment before you
start the engine.
W ~ h i S ps6 0 l is used throughout this
manual to warn ofpossible serious personal injury.
1- l
0
This symbol refers to possi6le equip-
ment damage.
Fuels, electricalequipment, batteries,exhaustgasesand moving parts present potential hazards that could result in serious,
personal injury.Take carein followingthese recommended procedures.
SafetyCodes
0
.
All local,state and federal codes shoukl be consulted and
complied with.
This engine is not designed or intended for use in aircraft.
Any such use is at the owner‘s sde risk.
General
0
0
0
Provide appropriatefire extinguishers and install them in
convenient locations. Use an extinguisher rated ABC by
NFPA.
Make surethat all fastenerson the engine are secureand
accurately torqued. Keep guards in position over fans,
driving belts, etc.
If it is necessaryto make adjustments while the engine is
running, use extreme caution when dcseto hot exhausts,
moving parts, etc.
Protect Against Moving Parts
0
0
Do not wear loose clothing in the vicinity of moving parts,
such as PTO shafts,flywheels, blowers, couplings,fans,
beits, etc.
Keep your hands away from moving parts.
Batteries
0
0
0
Before starling work on the engine,disconnect batteries
to prevent inadvertent starting of the engine.
DO NOTSMOKEwhile servicing batteries. Lead acid batteries give off a highly explosive hydrogen gas which can
be ignited by flame, electrical arcing or by smoking.
Verify battery polarity before connecting battery cables.
Connect negative cable last
Fuel System
0 DO NOT fill fuel tanks while engine is running.
DO NOT smoke or use an open flame in the vicinity of the
engine or fuel tank. Internal combustion engine fuels are
highly flammable.
Fuel lines must be of steel piping, adequately secured,
and free from leaks. Piping at the engine should be approved flexible line. Do not use copper piping for flexible
lines as copper will work harden and become brittle
enough to break.
Be sure all fuel supplies have a positive shutoff valve.
,
,
Exhaust System
Exhaust products of any internal combustion engine are
toxic and can cause injury, or death if inhaled. All engine
applications, especially those within a confined area,
should be equipped with an exhaust system to discharge
gases to the outside atmosphere.
0
DO NOT use exhaust gases to heat a compartment.
0
Make sure that your exhaust system is free of leaks. Ensure that exhaust manifolds are secure and are not
warped by bob unevenly torqued.
Exhaust G a s Is Deadly!
Exhaust gases contain carbon monoxide,a poisonous gasthat
migM cause unconsciousnessand death. It is an odorlessand
colorless gas formed during combustion of hydrocarbon fuels.
Symptoms of carbon monoxide poisoning are:
0 Dizziness
0 Vomiting
0 Headache
0 Muscular Twitching
Weakness and Sleepiness
Throbbing in Temples
If you experienceany of these symptoms, get out into fresh air
immediately,shutdownthe unit and do not use until it h a s been
inspected.
The best protection against carbon monoxide inhalation is
proper installation and regular, frequentinspectionsof the complete exhaustsystem. If you notice a change in the sound or appearance of exhaust system, shut the unit down immediately
and have it inspectedand repaired at once by a competent mechanic.
Cooling System
0
Coolants under pressure have a higher boiling pointthan
water. DO NOT open a radiator pressure cap when cool-
ant temperatureis above212 degrees F (100 degrees C)
or while engine is running.
Keep The Unit And Surrounding Area Clean
0 Make sure that oily rags are not left on or near the engine.
0
Remove all unnecessarygrease and oil from the unit. Accumulated grease and oil can cause overheating and
subsequent engine damage and present a potential fire
hazard.
E4
Redistribution or publication of this document,
by any means, is strictly prohibited.
*
*
Table of Contents
TITLE
PAGE
General Information.................................................... 2
Specifications .......................................................... 3
Dimensions and Clearances ............................................ 4
Assembly Torques
6
Special Tools
6
Engine Troubleshooting
7
RCCK Installation.,
8
RCCK Fuel System ....................................................11
MCCK Fuel System .................................................... 15
Ignition System
28
Battery Charging System
30
OilSystem ........................................................... 33
35
RCCK Cooling System ...........................
MCCK Cooling System ................................................ 36
Starting System .......................................................
41
Engine Disassembly
46
Wiring Diagram
56
.....................................................
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................................................
....................................................
.......................................................
..............................................
............ .......
...................................................
........................................................
I
WARNING
h
INCORRECT SERVICE OR REPLACEMENT OF PARTS MIGHT RESULT IN
SEVERE PERSONAL lNJURY AND/OR EQUIPMENT DAMAGE SERVICE
PERSONNEL MUST BE QUAllFlED TO PERFORM ELECTRICAL AND/OR
MECHANlCAL SERVICE
.
.
1
Redistribution or publication of this document,
by any means, is strictly prohibited.
General Information
Y
INTR0 DU CTION
ENGINE MODEL REFERENCE
This manual deals with specific mechanical and electrical information needed by engine mechanics for
troubleshooting, servicing, repairing, or overhauling
the engine.
Identify your model by referring to the MODEL and
SPEC (specification) NO. as shown on the unit
nameplate. Always use this number and the engine
serial numberwhenmaking referencetoyour engine.
Use the table of contents for a quick reference to the
separate engine system sections.
How to interpret MODEL and SPEC NO. on generator
set engines.
The troubleshooting guide is provided as a quick
reference for locating and correcting engine trouble.
The illustrations and procedures presented in each
section apply to the engines listed on the cover. The
flywheel end of the engine is the front end so right
and left sides are determined by viewing the engine
from the front.
The disassembly section contains major overhaul
procedures for step by step removal, disassembly,
inspection, repair and assembly of the engine
components.
If a major repair or an overhaul is necessary, a competent mechanic should either do the job or supervise
and check the work of the mechanic assigned to do
the job to ensure that all dimensions, clearances and
torque values are within the specified tolerances.
The wiring diagram on the last page of the manual
shows how the electrical components are interconnected.
A parts catalog (available at the dealer level) contains
detailed exploded views of each assembly and the
individual piece part numbers and their proper names
for ordering replacement parts.
1
2
3
4
5 6
Indicates kilowatt rating.
Series identification.
Voltage code of the generator.
Method of starting: A-automatic, R-remote
electric starting, and E-electric starting.
5. Factory code for designating optional eguipment,
if any.
6. Specificationletter which advances when the factory makes production modifications.
1.
2.
3.
4.
How to interpret MODEL and SPEC NO on industrial
engines.
T-T’T1
1
2
3
4
1. Factory code for general identification purposes.
2. Specific Type:
Use only Genuine Onan replacement parts to ensure
quality and the best possible repair and overhaul
results. When ordering parts, always use the complete Model and Spec number as well as the Serial
number shown on the nameplate.
MS-ELECTRIC starting with stub shaft, starter
and generator.
3. Factory code for optional equipment supplied.
4. Specification(Spec Letter) advances with factory
production modification.
Redistribution or publication of this document,
by any means, is strictly prohibited.
Specifications
.
.
This manual contains SI metric equivalents that follow immediately in parentheses
after the US.customary units of measure.
UNIT OF
MEASURE
SPECIFICATION
Number of Cylinders
Bore
Stroke
Displacement
Compression Ratio
Rated Speed (Maximum)
Power at
Rated Speed
Oil Filter
Oil Capacity Without
Filter
Oil Capacity With
Filter Change
Crankshaft Rotation
(viewed from flywheel)
Governor
Valve Clearance (Cold)
Intake
Exhaust
Spark Plug Gap
-
Breaker Point Gap Static
(Full Separation and Engine Cold)
Ignition Timing
in
(mm)
in
(mm)
cu in
(cm3)
RPM
BHP
(kW)
Qt
(litre)
Qt
(litre)
SERIES
MCCK
RCCK
2
3.250
3.000
(76.2)
49.8
(816)
7.0 to 1
1800
13.0
(9.7)
Full Flow
4
(3.8)
2
3.250
(82.55)
3.000
(76.2)
49.8
(816)
7.0 to 1
3900
19.5
(14.5)
Full Flow
3.5
(3.3)
NA
4.0
NA
(3.8)
(82.55)
Clockwise
Clockwise
Mechanical
in
(mm)
in
(mm)
in
(mm)
in
(mm)
BTC
0.012
(0.30)
0.012
(0.30)
0.025
(0.64)
0.020
(0.51 )
20"
0.012
(0.30)
0.01 2
(0.30)
0.025
(0.64)
0.020
(0.51 )
20"
*
3
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by any means, is strictly prohibited.
Dimensions and Clearances
.
All clearances given at room temperature of 70°F (21°C)All dimensions in inches (approximate millitnetre dimensions in
parentheses) unless otherwise specified
.
MINIMUM
DESCRIPTION
CYLINDER BLOCK
Cylinder Bore Honed Diameter .........................................
Maximum Allowable
Taper ................................................................
Out-of-Round .......................................................
Main Bearing Inside Diameter (Without bearing) ........................
Main Bearing Inside Diameter (Installed) ................................
Camshaft Bearing Bore (Bearing installed) ..............................
CRANKSHAFT
Main Bearing Journal Diameter .........................................
Main Bearing Clearance ................................................
Connecting Rod Journal Diameter......................................
Crankshaft End Play ...................................................
CONNECTING ROD
Large Bore Diameter (Without bearing installed
and rod bolts properly torqued) ......................................
Connecting Rod Side Clearance........................................
Piston Pin Bushing Bore (Without bearing) .............................
Piston Pin Bushing Bore with Bearing.
(Finished bore) ......................................................
Bearing to Crankshaft Clearance
Nodular Iron Rod ....................................................
Aluminum Rod ......................................................
(mm)
Inches
(mm)
3.2490
(82.525)
3.2500
(82.550)
2.187
2.0020
1.3760
(55.55)
(50.85)
(34.95)
0.005
0.002
2.188
2.0030
1.3770
(0.127)
(0.051)
(55.58)
(50.88)
(34.98)
1.9992
0.0025
1.6252
0.006
(50.78)
(0.064)
(41.28)
(0.152)
2.0000
0.0038
1.6260
0.012
(50.80)
(0.097)
(41.30)
(0.305)
1.7505
0.0020
0.8115
(44.46)
(0.051)
(20.61)
1.7510
0.0160
0.8125
(44.48)
(0.406)
* (20.64)
0.7504
(19.05)
0.7508
(19.07)
0.0005
0.0020
(0.013)
(0.051)
0.0023
0.0033
(0.058)
(0.084)
(34.90)
1.3745
(0.038)
0.0030
(0.076) 0.0120
0.300 (7.62)
(34.91)
(0.076)
...............................................................
PISTON
Clearance in Cylinder
Measure 90" to pin 0.10 inch below oil ring ...........................
Piston Pin Bore
Ring Groove Width
Top 1Compression Ring ............................................
No.2 Compression Ring .............................................
No 3 Oil Control Ring ...............................................
MAXIMUM
Inches
CAMSHAFT
1.3740
Bearing Journal Diameter ..............................................
Bearing Clearance ..................................................... 0.0015
End Play
0.0030
Camshaft Lift ..........................................................
(0.305)
........................................................ 0.7502
0.0025
(0.064)
(19.055)
0.0045 (0.114)
0.7506 (1 9.065)
0.0960
0.0955
0.188
(2.438)
(2.426)
(4.775)
0.0970
0.0965
0.189
.
4
.
.
(2.464)
(2.451)
(4.801)
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by any means, is strictly prohibited.
*
1
1
MINIMUM
Inches
(mm)
DESCRIPTION
PISTON PIN
Clearance in Piston
Clearance in Connecting Rod ......................................
Diameter ........................................................
PISTON RINGS
Clearance
Top Groove
Ring End Gap in Cylinder
INTAKE VALVE
Stem Diameter
Clearance (Stem to Guide)
Valve Face Angle
INTAKE VALVE SEAT
Valve Seat Width
Valve Seat Angle
€XHAUST VALVE
Stem Diameter ...................................................
Clearance (Stem to Guide)
Valve Face Angle
EXHAUST VALVE SEAT
Seat Cylinder Head Bore Diameter
Seat Outside Diameter
Valve Seat Width
Valve Seat Angle
VALVE GUIDE
Inside Diameter
TAPPET
Body Diameter
Bore Diameter
Clearance in Bore
VALVE SPRINGS INTAKE AND EXHAUST
Valve Spring Free Length (Approx.)
Valve Spring Length
Valve Open
Valve Closed
Spring Load @ 1.375 inch (Valve Closed)
Spring [email protected] 1.125 inch (Valve Open)
GEAR BACKLASH
Timing Gear
Oil Pump Gear
...............................................
MAXIMUM
Inches
(mm)
Thumb Push Fit
(0.005)
0.0007
(19.05)
0.7502
(0.018)
(19.06)
0.002
0.010
(0.051)
(0.254)
0.008
0.020
(0.203)
(0.508)
0.3425
0.0010
(8.70)
(0.025)
0.3430
0.0025
(8.71)
(0.064)
0.031
(0.787)
0.047
45"
(1.194)
0.3410
0.0025
(8.661) 0.3415
(0.064)
0.004
44"
(8.674)
(0.102)
..................................
............................................
.................................................
.................................................
1.1890
1.1920
0.031
(30.20) I .1900
(30.28)
1 .I930
0.047
(0.787)
6" .
(30.23)
(30.30)
(1.194)
..................................................
0.344
(8.74)
0.346
(8.79)
0.7475
0.7505
0.0015
(1 8.99)
(19.06)
(0.038)
0.7480
0.7515
0.003
(19.00)
(19.09)
(0.076)
....................................................
.........................................
...................................................
........................................
.................................................
.................................................
.................................................
........................................
.................................................
...................................................
...................................................
................................................
.................................
.................................. .................
...................................................
.............................
.............................
.....................................................
...................................................
5
0.0002
0.7500
44"
1.662 . (42.21)
38 ib.
71 Ib
1 .125 (28.58)
1.375 (34.93)
(17kg)
42 Ib.
(32kg)
79 Ib
(36kg)
0.002
0.002
(0.051)
(0.051)
(0.076)
(0.127)
0.003
0.005
(19 kg)
Redistribution or publication of this document,
by any means, is strictly prohibited.
Assembly Torques
TABLE 1.
The torque values given in Table I have been determined for the specific applications. Standardtorque
values must not be used where those listed inTable1
apply. The engine assembly torques given here will
assure proper tightness without danger of stripping
threads. All threads must be clean and lubricated with
new engine oil before torquing.
TORQUE
DESCRIPTION
SPECIFICATION
E#
-1 k
I ..-LY.
....
.........
.................
............
..........
Cylinder Head Capscrews
Rear Bearing Plate..
Connecting Rod Bolt
Iron Rod
Aluminum Rod
Flywheel Capscrew
Starter Mounting Bracket to
Oil Base Screws
Gear Case Cover
Oil Pump..
Intake Manifold
Exhaust Manifo Id
Oil Base..
...........
............
.................
.............
............
..................
Check all studs, nuts, and capscrews, and tighten as
required to keep them from working loose. Refer to
the PARTS MANUAL for the location of washers and
capscrews.
Nm
29-31
20-25
(39-42)
(27-34)
27-29
24-26
35-40
(37-39)
(33-35)
(48-54)
25-35
10-13
7-9
15-20
14-17
43-48
(34-47)
(14-18)
(10-12)
(20-27)
(1 9-23)
(58-65)
Special Tools
The following special tools are available from Onan.
For further information see TOOL CATALOG
900-0079.
Valve Seat Driver
Valve Guide Driver
Oil Guide and Driver
Combination Bearing Remover (Main and Cam)
Combination Bearing Driver (Main and Cam)
Flywheel Puller
6
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by any means, is strictly prohibited.
6
Engine Troubleshooting
.
7
Redistribution or publication of this document,
by any means, is strictly prohibited.
RCCK Installation
The type of installation can affect the life of the
engine, the cost of operation and the frequency of
necessary service. Plan the installation carefully to
ensure the best performance.
The fuel supply tank may be installed in any safe,
convenient location. If the tank is installed within the
engine enclosure, provide a vent line to theoutsideof
the enclosure. The top of the tank should be about 6
inches (152 mm) below the carburetor, but not more
than 4 feet (1.2 m) below the fuel pump.
Due to the great variety of uses, for the engine, these
installation instructions are typical and general in
nature. Use the installation recommendations given
as a general guide, improvising or altering as
necessary.
The installation of a fuel filter between the fuel tank
and the fuel pump is recommended. Any fuel filter
should be fitted with a shutoff valve and should be
easily accessible for cleaning.
GENERAL
Fuel leaks create fire and explosion
hazards whichmight result in severe
personal injury or death. Always use flexibk tubing
between engine and the fuel supply to avoid line
failure and leaks due to vibration. The fuel system
must meet applicable codes.
i
MOUNTING
WARNING
There are several acceptable methods of mounting
the engine. Among factors to be considered are:
location, method of coupling the engine to the load,
type of foundation or support, etc. The engineshould
be mounted level if possible. Maximum operation
angle is 15' sideways, 30' front to rear tilt. If the
engine will operate at an angle, besure to re-mark the
oil level indicator to compensate for the tilt.
CONNECT TO THE LOAD
The dimensions of various power take-off shafts are
as follows:
VENT1LATlON
The engine must be provided with asupply of fresh air
for radiator cooling and for combustion.
DIMENSIONS IN INCHES
Open Air Installation: For installations where the
engine is operated outside, ventilation usually is no
problem. However, in protecting the engine from the
elements, be sure nothing obstructs the flow of air
around the engine.
Standard
Rockford Clutch
Gear Reduction
EXHAUST
LENGTH
KEY
SIZE
1-1I2
(38.10 mm)
2-314
(69.85 rnm)
(9.53 mm)
1-7116
(36.51 mm)
(88.90rnrn)
318
(9.53 mm)
1-7/4
(31.75 rnm)
2-3/4
69.85 rnm)
(6.35 mrn)
1 DIAMETER
SHAFT
Vent exhaust gas outside enclosure. Shield the line if
it passes through a combustible wall or partition. If
turns are necessary, use sweeping type (long radius)
elbows. Increase one pipe size (from manifold outlet
size) for each additional 10 feet (3 m) in length.
Locate the outlet away from the engine air intake.
3-1/2
3/8
1I 4
KEEP SHAFTS OF ENGINE
AND LOAD PARALLEL
Plan the exhaust system carefully.
Exhaust gases are poisonous!
KEEP PULLEYS ALIGNED
WITH EACH OTHER
CARBURETOR AIR INTAKE
-
BELT IN TIGHTENED
AL
/ER
POSITION PULLING
LOAD
-
Proper engine efficiency depends upon a supply of
fresh air to the carburetor. Under special conditions,
it may be necessary to move the air cleaner off the
engine, using a longer connection hoseas necessary.
For extreme dust or dirt conditions, install a special
heavy duty air cleaner.
BELT IN LOOSENED
POSITION NOT
PULLING LOAD
-
FUEL SYSTEM
The engine uses a mechanical type fuel pump which
is mounted on top of the engine, adjacent to the
carburetor. A rubber fuel line connects the fuel pump
to the carburetor.
PULLEY
BRACKET T O KEEP
BELT OFF ENGINE
PULLEY
FIGURE 1. DRIVE BELT INSTALLATION
8
Redistribution or publication of this document,
by any means, is strictly prohibited.
,
.
Belt Drive: V-belts are preferable to flat.belts. CorfsOTf
a reliable belting supplier for recommendations
regarding size of pulleys, number of belts, etc.,
required. A typical belt drive installation is shown in.
Figure 1.
.
‘Install the clutch adapter, with drain slot downward
using two cap screws 3/8-16 x 2 inches on the low&
and onecapscrew3/8-16~1-3/4inchesontheupper
number 2 cylinder side (Cylinder nearer ~Iufck);
Install the 3/8-16. x ‘3-7/8‘inch stud .-through
:&t
adapter into the engine block upper remaining hole.
Use a lockwasher on each assembly screw. Use a
flatwasher and a lockwasher under the stud nut.
Comply with the following installation requirements:
1. Shafts of engine and load must be parallel with
each other.
2. Pulleys of engine and load must be in alignment.
3. Mount engine pulleys as close to engine as
possible.
4. If installation permits, belts should run horizon-,
tally.
5. Some method of disconnecting the load for
starting is recommended. If a clutch is not used, a
belt-tightener idler arrangement can be used.
Install the crankshaft key. Remove the clutch set
screw.
Install the clutch assembly (less housing) to the
crankshaft, driving it on carefully with a soft-faced
hammer until set screw hole is aligned. Install set
screw to bottom in Crankshaft hole, then back it out
one full turn. Tighten clutch retaining screws until
clutch is clamped securely to crankshaft. Lock the
screws and tighten the set screw.
Flexible Coupling: If a flexible coupling engine-toload drive is used, the load shaft must be in line and
‘centered with the eng-ineshaft, Figure 2.. .
ENGINE POWER
.
Smear grease over splined power take-off shaft.
Position the clutch throw-out collar to align the
grease fitting with the hole in the housing (number 1
‘cylinder side, horizontal). Pull the throw-out collar
outward to remove tension.
FLEXIBLE
Install the clutch housing so that the clutch throw-out
fork engages the throw-out collar. Be sure the
serrated shaft is properly meshed with the clutch
plate. Use two cap screws 7/16-14 x 2 inches on the
lower and onecapscrew7/1&14~1-3/4inchesonthe
upper number 2 cylinder side. Install the stud washer
and nut. Lubricate the two grease fittings just until
grease appears.
DISCARD
FIGURE 2 FLEXIBLE COUPLING
f
n
KEYWAY
3
n
I
Reduction Gear Drive: Reduction gear drives are
mounted at the factory (when ordered). The method
of connecting the load is the same as when connecting directly to the engine shaft.
CRANKSHAFT STUB SHAFT
IIY
*
Clutch Installation: A Rockford clutch can be installed at the factory or in the field. Install the clutch
according to the following instructions and Figure3.
CLUTCH
ASSEMBLY
Drill a 13/64 inch (5.2 mm) hole (or filed slot) in the
crankshaft for the clutch set screw. Locate center of
hole 11/32 inch (9 mm) from the end and directly
opposite the keyway in the crankshaft.
A867 CLUTCH
ADAP‘IE R
CLUTCH
HOUSING
TAKE-OFF
SET SCREW
..
.
SHAFT
.FIGURE 3. CLUTCH
INSTALLATION
Redistribution
or publication of this document,
by any means, is strictly prohibited.
9
BATTERY CONNECTIONS (Engines with
Electric Starter)
Connect the 12-volt battery positive cable to the
engine start switch terminal. Connect the battery
negative cable to the ground point on the engine oil
base, Figure 4.
FIGURE 4. BATTERY: CONNECTIONS
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by any means, is strictly prohibited.
10
RCCK Fuel System
GENERAL
Satisfactory engine performance is largely aependent upon correct fuel system adjustments. However,
adjustments cannot fully compensate for low engine
power due to wear, etc. If trouble develops, follow an
orderly procedure to determine the cause before
making
any adjustment.
.- .Adjusting the carburetor is a means of obtaining the
correct fuel-to-air mixture for smooth, efficient
operation. Always adjust in two steps, first the load
adjustment and then the idle adjustment.
GASOLINE CARBURETORS
Before adjusting the carburetor, be sure the ignition
system is working properly and the governor is
adjusted. Allow the engineto warm-up before starting
carburetor adjustments.
If carburetor is completely out of adjustment so the engine will not
run, open both valves 1 to 1-112 turns off their seats to permit
starting. Do not force the needlevalvesagainst theirseats.This can
bend the needle.
Adjustments
1. With no load, turn idle fuel adiustrnent out until
enginespeed dropsslightly below normal, Figure
5. Then turn needle in until speed returns to
normal.
2.-Apply a full load to engine.
3. Loosen packing nut and carefully turn main
adjustment in until speed drops slightly below
normal. Then turn needle out until speed returns
to normal.
4. Tighten packing nut.
3. Set idle fuel adjustment screw for even operation
so engine is firing on both cylinders and running
smoothly.
4. Release governor mechanism to allow engine to
accelerate. If engine accelerates evenly and
without a lag, the main adjustment is correct. If
not, adjust the needle outward about 1/2 turn and
again slow down the engine and release the
mechanism. Continue until the engine
accelerates evenly and without a time lag after
releasing the governor.
D
Loosen thepacking nut before making main fuel adjustment and then
tighten the nut to a snug fit affer the adjustment has
been made. Thisprocedure makes if easier to use the
carburetor adjusting fool and prevents fuel leaks
around the packing nut. Fuel leaks cause hard starting because the float level becomes lower than
normal.
Cleaning and RepaicTo clean thecarburetor, soak all
components thoroughly in a good carburetorcleaner
following the cleaner manufacturer's instructions. Be
sure all carbon is cleaned from the carburetor bore,
especially in the area of the throttle valve. Blow out
the passages with compressed air. If possible, avoid
using wire to clean out the passages.
Cleaningsolutions fypically contain
strong chemicals fhaf may cause
injury if used improperly. Read all warning labels
before using.
I
WARNING
. _.
Alternate Method (No load adjustment possible)
1. Start engine and allow it to warm up.
2. Push in on governor mechanism to slow engine
down to about 400 to 500 rpm.
,
Check the adjusting needles and nozzle for damage.
If the float is loaded with fuel or damaged, replace it.
The float should fit freely on its pin without binding.
Invert the carburetor body and measure the float
level, Figure6. If necessary, bend thesmall lipthatthe
inlet valve rides on to adjust float level.
DIMENSION
SHOULD BE
I /%"
3/ 16"
A9,3 (3.2-4.8 mm)
I
FIGURE 5. GASOLINE CARBURETOR
-
FIGURE 6.
CHECKING FLOAT LEVEL
Redistribution or publication of this document,
by any means, is strictly prohibited.
AMBIENT TEMP.
60
(OF)
CHOKE OPENING (Inches)
65
70
75
85
80
90
95
100
1/8 9/64.5/32 11/64 3/16 13/64 7/32 15/64 1/4
.
OPENI NG
TEXT)
CHOKE
G2
-G
864
-
LOOSEN THIS
SCREW AND
ROTATE THE
ENTIRE COVER
ASSEMBLY
FIGURE Sa. THERMAL MAGNETIC CHOKE SEiTlNGS
Remove air cleaner and adapter to expose the
carburetor throat. Loosen the screw which secures
the choke body. Rotate choke body clockwise to
increase choke and counterclockwise to decrease
choke action (leaner mixture). Refer to Figure6a for
correct choke setting accordingto ambient temperature. Use drill rod or shank of drill bit to measure
choke opening.
Check the choke and throttleshaftsforexcessiveside
play and replace if necessary.
THERMAL MAGNETIC CHOKE
This choke uses a heating element and a heat
sensitive bimetal spring to open the choke. The choke
solenoid, actuated during engine cranking only,
closes the choke according to ambient temperature,
Figure 6a.
Disassembly and Repair: If choke will not heat properly, check for broken heater wire, high-resistance
connections,or broken lead wires to the bimetal and
heater assembly. With the element at room temperature, check the heater resistance with an ohmmeter.
The resistance should be about 30.6 to 37.4 ohms for
a 12 volt system. If the heater is defective, replace it
with a new one. When the start button is engaged, the
solenoid should cause thespring-loaded armature to
contact the solenoid core.
If adjustment is required, use the following instructions. Choke bimetal spring must be at ambient
temperature. Allow engine to cool at least one hour
before setting. Adjust choke by turning the choke
body, which engages a link connected to a bimetal
choke spring.
. 518
x
CHOKE PLATE
RETAINING RIN
O.D. x VJ6")
SOLENOID 'COIL
BIMETAL AND
HEATER ASSY
SOLENOID CORE
GROUND TERMINAL
GROUND LEAD
THERMO-MAGNETIC
CHOKE
SHAKEPROOF WASHER
-WASHER
NUT ( 5 / 1 6 - 18")
A076
FIGURE 6b.
(24/64 I D . x 9/16
>
O.D.
x 1/16")
THERMAL MAGNETIC CHOKE ASSEMBLY
12
Redistribution or publication of this document,
by any means, is strictly prohibited.
If this does not occur, checkfor broken lead wires ora
defective solenoid coil. There must be slack in the
lead wires between the choke body and the bimetal
and heater assembly. The solenoid coil resistance
should be 2.09 to 2.31 ohms in a 12 volt system.
*-
i?
PARTS INCLUDED IN REPAIR KIT.
UPPERPUMPBODY
(NOT SERVICEABLE)
When replacing the cover on the thermostat and
heater assembly, be certain that the choke heater
lead wires have been correctly installed in the choke
housing. Improper replacement of the lead wires can
cause the choke assembly to malfunction.
*VALVE
G A S KQ
ET-Q~
*VALVE AND
VALVE CAGE
RETAINER
The wires enter the choke assembly through a small
notch that is cut in the edge of the housing. A cover
holds the wires in place and prevents movement
when tightened. When properly installed, the lead
wires will hang freely under the bimetal coil when the
choke is in either the open or closed position. The
end of the heater wire sleeve should be located from
1/8 inch inside the choke housing to flush with the
inside wall.
.*DIAPHRAGMASSEMBLY
*FUEL PUMP
ROD SPRING
*MOUNTING GASKET
'LOWER SIDE
DIAPHRAGM GASKET
When assembling the thermo-magnetic choke, the
bimetal and heater assembly is connected asfollows:
1. Lead tagged G goes to ground terminal on coil
solenoid.
2. Leadtagged H goes to either H1terminal on solenoid core.
ROCKER
ROCKER ARM
LINK'^^
BODY
FUEL PUMP
A diaphragm type fuel pump is used. If fuel does not
reach the carburetor, check thefuel pump. Todo this,
disconnect the fu.el line at the carburetor and, while
cranking the engine slowly by hand, observewhether
fuel cornesthrough theline. Besurethereisfuel in the
tank. If the line is open and no fuel comes throug h, the
pump is defective. Failure of the pump is usually due
to a leaking diaphragm valve or valve gasket, a weak
or broken spring, or wear in the drive linkage. Oil
diluted with gasoline may indicate a faulty
diaphragm. If the operator chooses to repair the
pump rather than install a new one, the use of a
complete repair kit is recommended.
FIGURE 6c. FUEL PUMP ASSEMBLY
4. Clean pump body thoroughly with solvent and a
fine wire brush. .
5. Holding upper pump body with diaphragm surface up, place new valve gasket into cavity.
Assemble valve spring and valves in cavity.
Reassemble valve retainer. Lock in position by
inserting and tightening valve retainer screws.
6. Place upper pump body assembly in a clean place
and rebuild lower body.
7. Holding lower body, press down on diaphragmto
compress spring under it, then turn bracket 90" to
unhook diaphragm so it can be removed.
a. Clean lower body with a solvent and a fine wire
brush.
9. Replace fuel pump rod spring, diaphragm gasket,
stand new spring in casting, position diaphragm,
compress spring and turn 90" to reconnect
d iaph ragm.
10. Hold lower body, then place upper body on it
(make sure that indicating marks are in line) and
insert the four screws. DO NOT TIGHTEN. With
hand on lower body only, push pump leverto limit
of its travel and hold in this position while
tightening the four screws. This is important to
prevent stretching the diaphragm.
11. Mount fuel pump on engine, using new mounting
gasket. Connect fuel lines.
=
Fuel leakage is a fire and explosion
hazard fbafmighf cause severe personal injury or death. Use care when reassembling
fuelpump. All parts must align perfectlyor pump will
leak fuel.
WARNING
Fuel Pump Reconditioning
1. Remove fuel lines and mounting screws holding
pump to engine, Figure 6c.
2. Makea mark with afileacrossapointwhere upper
and lower body join to assure proper reassembly.
Remove four assembly screws and remove upper
pump body.
3. Turn upper pump body over and remove valve
retainer screws and washers. Remove valve
retainer, valves, valve springs and valve gasket,
noting their position. Discard valve springs,
valves and valve retainer gasket.
13
Redistribution or publication of this document,
by any means, is strictly prohibited.
ADJUSTABLE GOVERNOR
Linkage
Where engine speed is governor controlled, the
governor is set at the factory to allow a nominal
engine speed of 2400 rprn at no-load operation
(unless another speed is specified when the engine is
ordered). Proper governor adjustment is one of the
most important factors in maintaining the power and
speed desired from the engine, Figure 6d.
Check the governor arm, linkage, throttle shaft and
lever for a binding condition or excessive slack and
wear at connecting points. A bindingcondition at any
point will cause thegovernortoact slowly and regulation will be poor. Excessive looseness will cause a
hunting condition and regulation will beerratic.Work
the arm back and forth several times by hand while
the engine idles. Replace parts as needed.
The engine starts at wide open throttle. The length of
the linkage connectingthe goverorarm tothethrottle
arm is adjusted by rotating the ball joint. Adjust length
so with the engine stopped and tension on the
governor spring, the carburetor throttle lever is wide
open. This setting allows immediate control by the
governor after starting and synchronizes travel of the
governor arm and the throttle shaft.
B A L L JOINT
SPEED ADJUSTING NUT
(TIGHTEN NUT TO
INCREASE SPEED)
SE NSlT IVlTY
Speed Adjustment
The speed at which the engine operates is determined by the tension applied to the governor spring.
Increasing spring tension increases engine speed.
Decreasing spring tension decreases engine speed.
The no-load speed of the engine should be slightly
higher than the speed requirementsof the connected
load. For example, if the connected load is to turn at
2310 rpm, set the no-load speed of the engine at
about 2400 rpm. Check speed with a tachometer. If a
speed adjustment is needed, turn the speed adjusting
nut in to increase the speed or out to decrease the
speed, Figure 6d.
8416
FIGURE 6d. GOVERNOR ADJUSTMENT LINKAGE
Before making governor adjustment, run the engine
about 10 minutes to reach normaloperating temperature. Be sure carburetor load and idle needles are
properly adjusted before checking or adjusting governor system. For an accurategovernoradjustment, a
reliable tachometer is required.
Sensitivity Adjustment
Theenginespeeddropfrom no loadtofull load must
be within 100 rpm. Check the engine speed with noload connected and again after connecting a fullrated load.
The sensitivity of the governor depends upon the
position of the arm end of the governor spring. A
series of holes in the governor arm provides for
adjustment. To increase sensitivity, move the governor spring toward the governor shaft. To decrease
sensitivity, move the governor spring toward the
linkage end of the governor arm.
n
Confacf wifh rofafing machinery
mighf cause serious personal injury
or deafh. S a y clear of rofating componenfs and
ensure that profecfive shields and guardsare in place
and secured before operating machinery.
WARNING
A too-sensitive setting will result in a surging speed (hunting)
condition, an alternate increase and decrease in engine speed. An
opposite settingwill result in too much speed variation between noload and full-load conditions.
Always recheck the speed adjustment after a sensitivity adjustment. Increasing sensitivity will cause a
slight decrease in speed and will require a slight
increase in the governor spring tension.
If the following checks do not remedy erratic operation, install a new governor spring. Springs become
fatigued with age.
14
Redistribution or publication of this document,
by any means, is strictly prohibited.
.
'
r-CCK Fuel System
’
4. Push in on governor mechanism to slow the unit
to400 to 500 rpm. Set idle needle for even operation so engine is firing on both cylinders and
running smoothly.
Satisfactory engine performance is largely dependent upon correct fuel adjustments. However, adjustments cannot fully compensatefor low engine power
due to wear, etc. If trouble develops, follow an orderly
procedureto determine the cause before making any
adjustment.
Adjusting the carburetor is a means of obtainingthe
correct fuel-to-air mixture for smooth, efficient operation. Always adjust in two steps, first the load
adjustment and then the idle adjustment.
Before adjusting the carburetor, be sure the ignition
system is working properly and the governor is
adjusted. Allow the engine to warm-up before starting carburetor adjustments.
A Zenith carburetor is used on Spec B-G engines.
Carburetor adjustments are the same as the Spec A
carburetor. The only difference is the location of
adjustment needles (Figure 7). The main-fuel adjustment needle (A) is on the bottom of carburetor.
FUEL IDLE
/ ADJUSTMENT
THROTTLE
S T O P S C R E W 4
CARBURETOR ADJUSTMENTS
(Spec A-G)
THIS DISTANCE
1/32 INCH
AT NO LOAD
If carburetor is completely out of adjustment so the
engine will not run, open both needles 1to 1-1/2 turns
off their seats to permit starting. Do not force needles
against their seats. This can bend the needle.
n
lnhalafion of exhausf gases mighf
result in serious personal injury or
death. Be sure deadly exhaust gas is piped outside
and away,from windows, doors or ofher inlets fo
building.
WARNING
MAIN FUEL
ADJUSTMENT
A
1. Apply a full load to engine.
2. Turn in load needle (Figure 7) until engine speed
drops. Then turn out needle until engine speed
returns to normal.
3. Remove load from engine.
4. Turn idle needle out until engine speed drops
slightly.Then turn needle in until speed returnsto
normal.
,
SPEC B-G
MAIN FUEL
ADJUSTMENT
Alternate Method (No-Load adjustment possible)
1. Start engine and allow it to warm up.
2. Push in on governor mechanism to slow the unit
down to about 400 to 500 rpm.
3. Release governor mechanism to allow theengine
to accelerate. If engine accelerates evenly and
without a lag, the load needle setting is correct. If
not, adjust needle outward about 1/2 turn and
again slow down the engine and release the
mechanism. Continue until engine accelerates
evenly and without a time lag after releasing
governor.
r
THROVLE STOP SCREW
SPEC A
FIGURE 7. ADJUSTING SIDEDRAFT CARBURETOR
15
Redistribution or publication of this document,
by any means, is strictly prohibited.
Throttle Stop Screw Setting
Throttle stop screw is located on the throttle shaft
lever (side of carburetor by ignition coil). It must be
adjusted and set for 1/32 inch clearance over the
manifold surface when the engine is running with no
load. See Figure 7a.
THIS DIMENSION
SHOULD BE
1/8 INCH i1/16 INCH
STARTING POSITION
IDLING POSITION
THROTTLE
,
[ STOP SCREW
nnv,
I LL
SETTHIS DISTANCE^ 1
AT 1/32 INCH WHEN
PLANT IS RUNNING
AT NO LOAD
PLATE
FIGURE 7c. FLOAT LEVEL ADJUSTMENT SPEC A
FIGURE 7a. THROTTLE STOP SCREW
CARBURETOR ADJUSTMENTS
(Begin Spec H)
Float Adjustment
To check float level, Figure 7b Spec B-G,Figure 7c
Spec A, remove the entire main fuel adjustment
assembly from float bowl (unscrew large nut from
float bowl. The proper level from float to bowl flange
gasket is1/8inch with fuel floatweight on needleand
spring. The float tab should just touch fuel inlet valve
and not compress inlet valve spring. Adjust by bending tab on the float.
The carburetor idle and main mixturescrews were set
for maximum efficiency at the factory and should
normally not be disturbed. If adjustments seem
necessary, first besurethe ignition system isworking
properly and is not the source of the problem.
If adjustment is needed, proceed as follows:
1. Turn both mixture screws in until lightly seated
(Figure7a),then back the idle mixturescrew out 1
turn and the main mixturescrew out 1-1/4 turns.
Do not apply excessive pressure fo
floafvalve.
Forcing fhemixfureadjusfmenf
screw fight will damage the
needle and seat Turn in on/y unfilright fension
can be felt
BEND T A B
GASKET
TAB CONTACTING
HEAD OF PIN, WITH
FULL WEIGHT OF FLOAT
COMPRESSING INLET
VALVE SPRING.
MAINFUEL
ADJUSTMENT
FS-1002
FIGURE 7d. DOWNDRAFT CARBURETOR ADJUSTMENT
2. Start the engine and allow it to warm up thoroughly (at least 10 minutes).
FIGURE 7b. FLOAT LEVEL ADJUSTMENT SPEC B-G
16
Redistribution or publication of this document,
by any means, is strictly prohibited.
3. Push in on governor arm to slow engine down to
about 400 to 500 rpm.
MINIMUM
FLOAT DROP
0.20 INCH
4, Release governor arm allowing engine to accelerate. If engine accelerates evenly and without
hesitation, main fuel adjustment is correct. If it
does not, turn the main adjustment screw out in
1/8 turn increments until the engine accelerates
smoothly, but do not turn it out morethan 1/2 turn
beyond the original setting.
5. Push in on governor arm to slow engine down to
about 400-500 rpm. Turn the idle adjustment
screw in until engine speed drops and then out
until engine speed drops again. Over a narrow
range between these two settings, engine speed
will be at its maximum. Set the idle adjustment
screw about 1/8 turn outward from the midpoint
of this range.
/
BEND FLOAT ARM
HERETO ADJUST
NO FUEL
FUEL LEVEL
0.25 INCH
Float Adjustment
Turn carburetor and check float setting (see Figure
7e). The float should be a specific distance from the
machined mating surface (without gasket). Bend the
float level. Bend the float arm as required to adjust
float drop.
FS-1524
FLOAT DROP ADJUSTMENTS
When checking float level and float drop, measure to float body,
not seam.
FIGURE 7e. FLOAT ADJUSTMENT BEGIN SPEC H
NEEDLE
AND SEAT
BEND FLOAT
TAB HERE
TO ADJUST
WALBRO
0.02 f 0.02 INCH
,
CARBU~ETOR
BODY
FLOAT LEVEL ADJUSTMENT
17
Redistribution or publication of this document,
by any means, is strictly prohibited.
CARBURETOROVERHAUL
B
Carburetion problems that are not corrected by mixture or float adjustments are usually a result of
gummed-up fuel passages or worn internal parts. The
most effective solution is a complete carburetor
overhaul.
In general, overhaulinga carburetorconsists of complete disassembly, a thorough cleaning, and replacement of worn parts. Carburetor repair kits are available that supply new gaskets and replacements for
those parts most subject to wear.
THROTTLE
SHAFT
AND LEVER
General instructions for overhauling a carburetorare
given below. Carefully note the position of all parts
while removing to assure correct placement when
reassembling. Read through all the instructions
before beginning for a better understanding of the
procedures involved. Carburetor components are
shown in Figures 8 and 8a.
CHOKE PLATE
-
THR
T
IDLE ADJUSTMENT
A
NEEDLE
a
Ignition of fuelmight cause serious
personal injury or death by fire or
explosion. Do not permit any flame, cigareffe, or
other igniter near the fuel system.
THROlTLE PLATE
FIGURE 8. DOWNDRAFT LUA CARBURETOR ASSEMBLY
Carefully note position of float assembly parts,
then slide out retaining pin and remove the float
assembly, any springs or clips, and the needle
valve.
Removal and Disassembly
1. Disconnectall lines, linkages, wires, and attaching nuts or bolts; then, remove the carburetor
from the engine. (Downdraft carburetors may
require removal of the intake manifold to disconnect.)
Unscrew and remove needle valve seat.
2. Remove air cleaner adapter, if so equipped, and
automatic choking assembly.
Cleaning and Repair
1. Soak all metal components not replaced by repair
kit in carburetor cleaner. Do not soak non-metal
floats or other non-metal parts. Follow the cleaner
manufacturer's recommendations.
3. Removethrottle and choke plate retaining screws,
then plates. Pull out throttle and choke shafts,
being careful not to damage the teflon coating
applied to some throttle shafts.
2. Clean all carbon from the carburetor bore, especially where the throttle and choke plates seat. Be
careful not to plug the idle or main fuel ports.
4. Remove main and idle mixturescrew assemblies.
5. On downdraft carburetors, remove attaching
screws and separate upper and lower carburetor
sections. On sidedraft models, unscrewthe retaining screw and remove fuel bowl from the upper
carburetor body.
3. Blow out all passages with compressed air. Avoid
using wire or other objects for cleaningthat may
increase the size of critical passages.
18
Redistribution or publication of this document,
by any means, is strictly prohibited.
IDLE
ADJUSTMENT NEEDLE
Bo
- S F L O A T AXLE
Yl ll!$
CHOKE SHAFT
POSITION HOOK
NDER TANG ON
HROTTLE PLATE
FLOAT SPRING
I
FLOAT
ASS EMBLY
FUEL BOWL
MAIN JET
ADJUSTMENT
POSITION O F SPRING
AFTER INSTALLATION
FIGURE 8 a SIDEDRAFT CARBURETOR ASSEMBLY
2. Rejoin upper and lower carburetor sections on
4. Check the condition of any needle valve not
included in repair kit and replace if damaged
(Figure 8b). Replace float if loaded with fuel or
damaged.
5. Checkthechokeand throttleshafts forexcessive
play in their bore, and replace if necessary.
6. Replaceold componentswith new parts included
in repair kit.
.
downdraft carburetors - fuel bowl and upper
carburetor body on sidedraft models.
n
Fuelleakageis a fireandexplosion hazard that miahf cause
severe personal injury or death. Use ;are when
reassembling carburetor. All parts must align
perfectly or carburetor will leak fuel.
WARNING
The float spring on Zenith sidedrafl carburetors rides on the
inner face of the fuel bowl. Be sure to catch the end of the
spring when reinstallingthe bowl (Figure Sa).
3. Slide in throttle shaft and install throttle plate,
using new screws if furnished in repair kit. Before
tighteningthe screws, the plate must be centered
in the bore. To do so, back off the throttle stop
screw as necessary and completely close the
throttle lever. Seat the plate by tapping with small
screwdriver, then tighten screws. Installthe choke
shaft and plate in the same manner.
4. Install main and idle mixture screw assemblies.
Turn in screws until lightly seated and then out
the number of turns specified.
FIGURE 8b. MIXTURE NEEDLE INSPECTION
Forcing the mixture adjustment
screws tight will damage the
needle andseat. Turnin only untillighttension is
felt.
Reassembly and Installation
1. Install needle valve and seat, fuel bowl gasket,
and float assembly. Make sure that all clips and
springs are properly placed and that the float
moves freely without binding. Check float level
and adjust as necessary (see Float Level Adjustment).
5. Reinstall carburetor on engine and connect fuel
lines, linkages, and wires.
6. Reset mixture screws according to directions
given earlier in this section. Install air cleaner
adapter, where used, and air cleaner.
19
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by any means, is strictly prohibited.
PUMP ASSEMBLY
I
FUEL PUMP TEST
Test the fuel pump by checking the pump outlet pressure. Use the following procedure.
1. Remove the fuel line from the pump outlet and
install a pressure gauge.
2. Press the START switch and hold it for several
seconds until pressure reading is constant.
3. Pressure reading should be 2-112 to 3-1/4 psi
(17.2 to 22.4 kPa). If the retension is good, the
pressure should stay constant or drop off very
slowly.
1
% 1
81
a]
1
GASKET
COVER
FS-1487
FIGURE 9. REMOVAL OF MAGNET AND FILTER
A low pressure reading with little or no pressure drop
indicates a weak or broken diaphragm or diaphragm
spring, worn linkage or leaky check valves. If pressure is above maximum, the pump diaphragm is too
tight or the diaphragm (or plunger) return spring is
too strong. Any of the above conditions are cause for
repair or replacement of the pump.
PUMP ASSEMBLY
PLUNGER
"0"RING SEAL
WASHER
ELECTRIC FUEL PUMP
FS-1486
FIGURE 9a. REMOVAL OF PLUNGER ASSEMBLY
The Facet and Bendix pumps incorporate a hollow
stainless steel plunger in a brass cylinder.The plunger
has no gland or seal, but is freely fitted. The fluid
being pumped provides the seal by filling the small
clearance between the plunger and cylinder. Energizing the pump's electric solenoid pulls the plunger
downward, compressing the return spring. When the
solenoid is de-energized, the return spring drives the
plunger back, delivering fuel to the pump outlet.
3. Using a thin nose pliers, remove the retainer
spring from the plungertube. Removethewasher,
O-ring seal, cup valve, plungerspring and plunger
from tube (Figure sa).
4. Wash all parts (except gasket and seal) in parts
cleaning solvent, Blow out solvent and dirt with
low pressure compressed air. Slosh the pump
assembly in cleaning solvent, blow dry and swab
the inside of the plungertubewith a cloth wrapped
around astick. If the plunger does not wash clean
or has rough spots, gently clean the surface with
crocus cloth.
DO not substitute automotive type
electric fuel pumps for sfandard
Onan supplied electric pumps. The output pressure
is much higher and can cause carburetor flooding or
fuel leakage, creating a fire hazard.
Most parts cleaning solvents
are flammable and could cause
serious personnel injury if used improperly. Follow the manufacturer's recommendations when
cleaning parts.
Fuel Pump Repair
Service of the Facet pump is limited to the bottom
cover, filter, plungertube, and plunger assembly. All
parts of the electric system are hermeticallysealed in
a gas atmosphere and are not serviceable. If electrical
failure occurs, replace the pump.
5. Insert plunger in tube, buffer spring end first.
Check fit by slowly sliding the plunger back and
forth in the tube. It should move fully without any
tendency tostick. If aclick cannot be heard as the
plunger is slid from one end to the other, the
internal pump assembly is not functioning properly and the pump should be replaced.
6. Install plunger spring, cup valve, O-ring seal and
washer. Compress the spring and install the
retainer with ends in the side holes of the tube.
7. Check cover gasket and replace if deteriorated.
Place cover gasket and magnet in the bottom
cover and install filter and cover assembly on
pump. Twist cover on by hand and tighten
securely with a 5/8-inch wrench.
Lzz2
Do not tamper with the seal at the
center of the mounting bracket on
the side of the pump as it retains the dry gas which
surrounds the electrical system. Electrical system
componentsare not serviceable.
Use the following procedure for servicing the pump:
1. Using a5/8-inch wrench, loosen, the pump cover,
then remove by hand.
2. Remove the filter, magnet and cover gasket (Figure 9).
20
Redistribution or publication of this document,
by any means, is strictly prohibited.
MECHANICAL FUEL PUMP
(Spec A-E)
A diaphragm type fuel pump is used. If fuel does not
reach carburetor, check the fuel pump. Be sure there
is fuel in the tank. If line is open and no fuel comes
through, pump isdefective. Failureof pump isusually
due to a leaking diaphragm valve or valve gasket, a
weak or broken spring, or wear in the drive linkage.
Oil diluted with gasoline may indicate a faulty
diaphragm.
VALVE.GASKETVALVE CAGE
RETAINER
DIAPHRAGM ASSEMBLY
Removal
1. Remove the fuel inlet and outlet lines from the
pump.
2. Remove the two capscrews holding the pump to
the engine.
3. Remove the pump, spacer (if used) and gasket
from the engine and discard the gasket.
MOUNTING GASKET
LOWER SIDE
APHRAGMGASK
PHRAGMRETURN
ROCKER ARM
ROCKER ARM LIN
Installation
1. Remove all gasket material from mounting faces
and spacer (if used). Apply oil-resistant sealer to
both sides of the gasket(s) and to the threads of
the attaching capscrews.
2. Place the gasket (and spacer if used) on the
mounting face of the pump. Slide the mounting
capscrews through the pump and gasket (and
spacer) to prevent the gasket from slipping out of
place.
3. Lightly place the pump in position on the engine,
making sure the rocker arm is riding on the camshaft lobe. Start both capscrews and check for
proper gasket placement. Alternatelytorque capscrews to specifications.
4. Connect the fuel inlet and outlet lines.
5. Operate the engine and check for leaks.
FIGURE 9b. EXPLODED VIEW OF PUMP
4. Detachthe pump diaphragm by pressing its metal
base into the pump body and turning it 1/4 turn.
(Figure 9b).
5. The rocker arm return spring can normally be
removed without removal of the rocker arm from
the pump body. Use a small screwdriver or
tweezers to compress the spring and tip it off the
rocker arm catch. When installing the new spring,
make sure it is properly placed before remounting the pump.
6. Clean in solvent all pump parts that will not be
replaced and allow to dry.
7. Install the new valve and cage assemblies and
their gaskets in the retainer. Be sure the assemblies are in proper position and fullyseated. Reinstall the retainer and assemblies in the pump
upper body.
8. To install the new pump diaphragm, turn the
pump lower body upside-down and place the
diaphragm and spring in the body. Pressthe base
of the diaphragm up into the body of the pump
and turn 1/4 turn.
9. Install new rocker arm return spring. Check for
proper spring placement.
Repair
Repair kits are available that provide replacement
parts for the pump which are most subject to wear.
Use all parts included in the repair kit. Proceed as
follows:
1. After the pump is removed from the engine,
scribealineon the flangesofthe upperand lower
pump bodies to assure correct positioning when
reassembling.
2. Remove the securing screws and separate the
upper and lower pump bodies.
3. Detach the valve cage retainer from the pump
upper body. Noting their position, remove the
valve and cage assemblies and their gasketsfrom
the retainer (Figure 9b).
21
Redistribution or publication of this document,
by any means, is strictly prohibited.
FUEL FILTER (Begin Spec F)
10. Place the upper and lower bodies of the pump
together with the scribe marks aligned. Start the
four securing screws, making sure they do not
chew into the diaphragm fabric. Leavethe screws
2 Or 3 turns loose.
Electric pumps incorporate a filter within the casing
of the pump (Figure loa). Use a 5/8 inch wrench to
twist off the bottom of the pump and removethe filter
element. If the filter is dirty, replace it along with the
cover gasket.
11 Operate the rocker arm several times to flex the
new diaphragm. While holding the rocker arm
fully flexed, tighten the body screws.
fq
I",?
az
Failure to flex the rocker arm
fully while tightening the pump
bodies together will result in excessive pump
pressure and possible engine flooding or pump
diaphragm failure.
LECTRIC FUEL
FUEL FILTER (Spec A-E)
Periodic maintenance should consist of cleaning the
fuel filter, flame arrestor, carburetor, and complete
carburetor adjustment.
-
Remove fuel sediment bowl, empty, clean, and dry
(Figure 10). Remove screen and clean any trapped
particles. When replacingthe sediment bowl, besure
screen and gasket are in place.
GASKET
FS-1488
FIGURE
loa. BENDIX AND FACET ELECTRIC PUMP FILTER
AUTOMATIC CHOKES
Automatic chokes may occasionally require adjustment to provide the best fuel-to-air mixture for the
existing temperatureconditions. Several adjustments
may be necessary to arrive at the correct setting. Let
the engine cool to ambient air temperature between
each adjustment.
If theenginestarts,runsforafew minutes, then stops,
the choke mixture may be too lean. If the engine
starts, but runs rough and is sluggish once it has
warmed up, the choke mixture may be too rich.
FIGURE 10. FUEL FILTER
22
Redistribution or publication of this document,
by any means, is strictly prohibited.
AMBIENT TEMP.
60
(OF)
CHOKE OPENING (Inches)
1/8
65
70
75
80
85
90
95
9/64 5/32 11/64 3/16 r3/64 7/32 15/64
100
1/4
CHOKE OPENING
-
LOOSEN THIS
SCRW AND
ROTATE THE
YI
-G
ENTIRE COVER
GZ-
ASSEMBLY
864
FIGURE 11. THERMO-MAGNETIC CHOKE SETTINGSAND ADJUSTMENTS
Thermo-Magnetic Chokes (Spec A-G)
1. Loosen the screw which secures the choke body
assernbly.
2. Rotate the choke body until the correct choke
setting is attained. Figure11, lists the correct settings for various temperature conditions.
3. Start the engine and observe its operation. Slight
readjustmentof the choke setting may be necessary for best engine operation.
4- Retighten the securing screw when adjustment
has been completed.
Thermo-magnetic chokes have a strip-type heating
element attached directly to a bi-metal coil (Figure
11a). As the element heats, the coil twists and gradually opens the choke valve. An electromagnetic solenoid pulls the coil in tighter during engine starting to
increase the choking effect. The coil is calibrated to
provide the correct choke setting under various
temperature conditions.
Adjustment Adjustment of the choke setting must be
made with the engine cold. Do not attempt adjustment until the engine has been shut down for at least
an hour. Refer to Figures 11and 11a and proceed as
follows:
THERMO-MAGNETIC
CHOKE
‘
NUT (5/16- 18”)
-WASHER
>
(24/64 I.D. x 9/16 O.D. x 1/16 ”)
A876
FIGURE l l a . THERMO-MAGNETIC CHOKE ASSEMBLY
23
Redistribution or publication of this document,
by any means, is strictly prohibited.
Repair: If choke will not heat properly, check for
broken heater wire, high-resistance connections, or
broken lead wires to the bi-metal and heater assembly. With the element at room temperature, check the
heater resistance with an ohmmeter. The resistance
should be about 30.6 to 37.4 ohms for a 12 volt system. If the heater is defective, replace it with a new
one. When the start button is engaged, the solenoid
should cause the spring-loaded armature to contact
the solenoid core.
If this does not occur, check for broken lead wiresora
defective solenoid coil. There must be slack in the
lead wires between the choke body and the bi-metal
and heater assembly. The solenoid coil resistance
should be 2.09 to 2.31 ohms in a 12 volt system.
ELECTRIC CHOKE
The choke consists of a bi-metal coil and an electric
heating element. The bi-metal coil connects to the
choke shaft and holds the choke plate nearly closed
when the engine is cold.
-
As theenginestarts, current is supplied to the electric
heating element in the choke cover. Heat from the
element causes the bi-metal coil to twist. The twisting
action of the coil turns the choke valve shaft and
gradually opens the valve. Heat from the element
keeps the choke open while the engine is running.
'
The choke cover gets very hot during normal operation and can cause
serious burns if touched. Do not touch the choke
cover while the engine is operating.
WARNlNG
When replacing the cover on the thermostat and
heater assembly, be certain that the choke heater
lead wires have been correctly installed in the choke
housing. Improper replacement of the lead wires can
cause the choke assembly to malfunction.
'
If the engine starts but runs roughly and blows out
black smoke after a minute or two of operation, the
choke is set too rich. If the engine starts but sputters
or stops before it warms up, the choke is set too lean.
The wires enter the choke assembly through a small
notch that is cut in the edge of the housing. A cover
holds the wires in place and prevents movement
when tightened. When properly installed, the lead
wires will hangfreely underthe bi-metal coil when the
choke is in either the open or closed position. The
end of the heater wire sleeve should be located from
1/8 inch inside the choke housing to flush with the
inside wall.
When assembling the thermomagnetic choke, the
bi-metal and heater assembly is connected as follows:
Adjustment: Table 2 lists average choke settings.
Loosen the two mounting screws and rotate the
choke cover until the correct setting is attained.
Check the setting by starting the engine and observing its operation. Be sure to retighten the mounting
screws after adjustment (See Figure 12).
1. Lead tagged G goes to ground terminal on coil
solenoid.
2. Lead tagged H goes to either H1terminal on solenoid core.
TABLE 2. CHOKE SPECIFICATIONS
L
CATCH OUTER END
OF COIL IN SLOT
IN COVER TAB
AVERAGE CHOKE SETTING
AMBIENT TEMP
CHOKE OPENING
I
I
I
40" F
4.4O
70' F
21°C
c
I
7/32 to 9/32 inch
5.6 to 7.1 rnm
11/32 to 13/32 inch
8.9 to 10.4 mm
I
I
I
COVER
INSERT INNER END
OF COIL IN SLOT
IN SHAFT
MOUNTING SCREWS
THIS
WAY
FOR
RICHER
MIXTURE
FS 1484
'
i
FOR
A
LEANER
MIXTURE
CHOKE PLATE
LOOSEN THESE
SCREWS AND
L MEASURE CHOKE SETTING
ROTATE THE
ENTIRE COVER
HERE
ASSEMBLY
FIGURE 12. ELECTRIC CHOKE ADJUSTMENT
24
Redistribution or publication of this document,
by any means, is strictly prohibited.
'
Repair: If the choke fails to operate, check to see if
the heating element is working. If it is, the choke
cover should become hot after a few minutes of
engine operation. If the cover does not get hot,
check for current at the cover terminal. The engine
must be running. Trace down any opens or shorts.
Remove the choke cover to inspect the heating element and coil. Seethat the element is not burned out
or broken. The bi-metal coil must not be damaged,
dragging in the housing, or have an improperly
directed spiral.
When installing a new coil, maintain the original
direction of spiral inward from the fastening screw.
Besurethe coil setssquarely in the housing so itwill
not bind. Coil should not touch inside of choke
body.
.
.
.
25
Redistribution or publication of this document,
by any means, is strictly prohibited.
FIXED SPEED GOVERNOR
Besureto clean, check, and lubricategoveror linkage
(steel ball joints) before making any adjustments.
Binding in the linkage joints can cause erratic operation. Some early models used plastic balljoints which
require no lubrication.
Before making governor adjustment, run, the engine
about 10 minutes to reach normal operatingtemperature. Be sure carburetor load and idle needles are
properly adjusted before checking or adjusting governor system. For an accurate governor adjustment, a
reliable tachometer is required.
If the following checks do not remedy erratic operation, install a new governor spring. Springs become
fatigued with age.
Confacf with rotating machinery
mighf cause serious personal injury
or death. Sfay clear of rofafing components and
ensure fhaf protective shields andguards are in place
and secured before operafingmachinery.
Governor and vacuum booster control engine speed
(Figure 13). Rated speed and voltage appear on
nameplate. On a 4 pole generator engine speed
divided by 30 equals frequency.
r
THROTTLE
STOP SCREW
INTERNAL SPRING
BRACKET
THIS DISTANCE1/32 INCH
AT NO LOAD
VACUUM
BOOSTER
CARBURETOR
THROTTLEARM
CARBURETOR
THROTTLE ARM
CARBURETOR
THROTTLE
THIS
DISTANCE
DETERMINES
SENSITIVITY
GOVERNOR LINKAGE
JOINT
RING BRACKET
ADJUSTING STUD
ADJUSTMENT
FIGURE 13. GOVERNOR AND GOVERNOR ADJUSTMENTS
26
Redistribution or publication of this document,
by any means, is strictly prohibited.
.
.
Vacuum-Booster Adjustment
1. After sensitivity adjustment, connect booster external spring to slide on governor link (Figure
13a).
2. With engine running at no-load, move adjustable
slide to point where there is no tension on spring.
3. Apply full-rated load to engine.
Thus, 1800 rprn gives a 60 hertz frequency, and 1500
rprn gives 50 hertz frequency.
Preferred speed varies approximately 3 hertz from
no-load to full-load operation. Be sure throttle, linkage, and governor mechanism operate smoothly.
Linkage
*
4. If speed increases more than at no-load, lessen
internal spring tension of the booster. To change
tension, pull out spring bracket and move the pin
toadifferent hole (Figure 13a). If speed decreases
when load is applied, increase internal spring
tension of the booster.
The engine starts at wide open throttle. Length of
linkage connecting governor arm to throttle arm is
adjusted by rotating the ball joint. Adjust length so
that with engine stopped and with tension on governor spring, the stop screw on carburetor throttle lever
is 1/32 inch from the stop pin. This setting allows
immediatecontrol by the governor after starting, and
synchronizes travel of governor arm and throttle
shaft. See Figure 13.
VACUUM
BOOSTER
Speed Adjustment
1. Start engine and allow to warm up without load.
n
Inhalation of exhaust gases
might result in serious personal
injury or death. Be sure deadly exhaust gas is
piped outside and away from windows, doors or
other inlefs to building.
WARNING
EXTERNAL
SPRING
2. Remove vacuum booster external spring from
bracket slide on the governor link (Figure 13).
3. Refer to voltage and speed charts. If needed,
increase speed by increasing tension on the governor spring. Decrease tension on the governor
spring to reduce speed.
4. Add a full-rated load to the engine and compare
lower speed and voltage with those shown in the
charts. If operation does not remain within these
limits, check governor linkage and governor
spring, and, if necessary, follow preceding procedure again.
FIGURE 13a. VACUUM BOOSTER
SPEED CHART FOR
CHECKING GOVERNOR REGULATION
60 HERTZ
AC GENERATING SETS
5. Check and, if necessary, adjust governor sensitivity (see Sensitivity Adjustment).
Maximum No-Load Speed
RPM
Frequency (Hz)
Minimum Full-Load Speed
(Without Booster)
RPM
Frequency (Hz)
Sensitivity Adjustment
1. Start engine and allow to warm up.
2. Check voltage and speed, first without load and
then with a full load. See voltage and speed
charts.
3. Increasesensitivity (closer regulation) by shifting
adjusting clip toward governor shaft (Figure 13).
Move clip away from governor shaft to decrease
sensitivity.
I
I
1890
63
50 HERTZ
I
1560
52
1770
1490
59
49
VOLTAGE CHART FOR
CHECKING GOVERNOR REGULATION
AC GENERATING SETS
Too muchsensitivity causes engine to hunt.Toolittlesensitivity results in too much speed differencebetween no-load and
full-load conditions.
Maximum No-Load Volts
Minimum Full-Load Volts
(Without Booster)
4. A change in sensitivity adjustment usually requires a compensating speed adjustment (spring
tension). Then proceed to vacuum booster adjustment.
27
120 VOLT
(1 PH . 2 W)
OR
1201240 V
(1 PH.3 W)
240 VOLT
(1 PH. 2W)
OR
240 VOLT
(3 PH. 3W)
126
252
110
, 220
Redistribution or publication of this document,
by any means, is strictly prohibited.
Ignition System
3. Removetwo mountingscrews (A) and pull points
out of box just far enough so screw B can be
The engine is equipped with an automotive type battery ignition system. Both spark plugs fire simultaneously, thus the need for a distributor is eliminated.
The major components of the ignition system are: the
spark plugs, coil, breaker points and condenser. The
MCCK ignition system is shielded to prevent radio
interference.
removed. See Figure 15. Replace points with a
new set but do not completely tighten mounting
screws (A).
4. Rotate crankshaft clockwise (facing flywheel) by
hand until points are fully open. Turn screw (C)
until point gap measures 0.020 inch (0.51 mm)
with a flat thickness gauge.
IGNITION COIL
To test primary and secondary windings within the
ignition coil proceed as follows:
1. Use a Simpson 260 VOM or equivalent.
2. Place black lead on ground (-)terminal of coil and
red lead to positive (+) terminal. Primary resistance should read:
RCCK 3.87-4.73 ohms
MCCK 1.OO--1.10 ohms.
3. Change resistance setting on ohmmeter. Place
ohmmeter leads inside of spark plug cable holes
(Figure 14). Secondary resistance should read:
RCCK 12,600-15,400 ohms
MCCK 10,800-13,200 ohms.
5. lighten mounting screws and recheck gap.
6. Proceed to lgnition Timing.
Eachtime new breakerpoints are installed, placea drop of oil
on the breaker arm pivot.
PLACE DROP OF OIL ON PIVOT POINT
WHENEVER NEW POINTS ARE
INSTALLED.
REFERENCE MARK)’
c
FOR
OHMMETER
---
AP-.P_ROXIMATETIMING
’LOOSEN SCREWS
-AND SHIFT BOXADVAVCE OR--
20
FIGURE 14. TESTING IGNITION COIL
4. If any of the above conditions are not met, replace
coil. Refer to PARTS CATALOG for correct part
number.
FIGURE 15. IGNITION TIMING
BREAKER POINTS
IGNITION TIMING
Ignition Timing Engine Running
-
The timing is adjusted during initial engine assembly
and is fixed bythe point gap adjustment. To maintain
maximum engine efficiency, change the breaker
points every 200 hours of operation.
1. Remove two screws and cover on breaker box.
2. Remove both spark plugsso engine can beeasily
rotated by hand. If plugs have not been changed
within last 100 hours, replacethemwith new ones
after setting breaker points.
Always check timing after replacingignition points or
if noticing poor engine performance. Proceed as
follows:
1. To check ignition timing accurately, use a timing
light when engine is running. Connect timing
light according to manufacturer’s instructions.
Either spark plug can be used as they fire simultaneously.
28
Redistribution or publication of this document,
by any means, is strictly prohibited.
*
3. Lamp should go out just as points open (20"BTC)
2. Place a white chalk or paint mark on flywheel TC
3.
4.
5.
6.
and ignition occurs. Timing marks should align.
mark.
Start engine and check timing. The TC on flywheel should line up with correct timing mark
(20'BTC).
If timing needs adjustment, loosen breaker box
mountings screws and move left to advance or
right to retardtiming (when facing rear of engine).
Be sure mark on flywheel lines up with correct
timing mark.
Replace breaker box cover and any other hardware removed.
Ignition Timing
4. If timing needs adjustment, loosen mounting
screws on breaker box and move left to advance
or right to retard timing (when facing rear of
engine).
SPARK PLUGS
Check, and regap spark plugs every 100 hours of
operation (Figure16). Replacespark plugs that show
signs of fouling or electrode erosion.
- Engine Not Running
1. Connect a continuity test lamp set across ignition
breaker points. Touch one test prod to breaker
box terminal to which the coil lead is connected
and touch other test prod to a good ground on
engine.
2. Turn crankshaft against rotation (counterclockwise) until points close. Then slowly turn crankshaft with rotation (clockwise).
FIGURE 16. SPARK PLUG GAP
29
Redistribution or publication of this document,
by any means, is strictly prohibited.
Battery Charging System
BATTERYCARE
Check battery cells with a hydrometer. The specific
gravity reading should be approximately 1.260 at
77°F (25OC).
Weak ignition spark or a discharged battery indicate
trouble in the charging system. But before testing the
charging system, always check the battery for serviceability.
If one or more cells are low on water, add distilled
water and recharge. Keep the battery case clean and
dry. An accumulation of moisturewill lead to a more
rapid discharge and battery failure.
Keep these points in mind when testing or servicing
the flywheel alternator:
1. Be sure output control plug (connector) is inserted properly. The plug must bottom in receptacle-eliminates any resistance due to a poor
connection. Keep clean and tight.
2. Make sure alternator stator leads are not shorted
together.
3. Be sure regulator-rectifier output control has a
good ground connection. Mating surface for
mounting must be clean and fasteners tightened
properly.
4. Never reverse the battery leads.
Keep the battery terminals clean and tight. Push the
cable terminal down flush with or slightly below the
top of the battery post. After making connections,
coat the terminals with a light application of petroleum jelly or grease to retard corrosion.
Poor contact at the battery cable connectionsis oflen a source of
trouble. Make sure battery cables are in good condition and that
contacting surfaces are clean and tightly connected. Do not
reverse battery leads. Use recommended battery tools when disconnecting leads to avoid mechanical battery damage.
Ignition of explosive battery gases
might cause severe personal iniury.
Do not smoke while servicing batteries.
i
WARNING
Charging system tests require a fully charged battery.
BATTERY CHARGING, ALTERNATORS
15 AMP FLYWHEEL ALTERNATOR
SYSTEM
The flywheel alternator is a permanent magnet alternator and uses asolid-state voltage regulator-rectifier
for controlling output. Figures 17 and 18.
The 15 amp system has two white wires coming from
stator and is used on 3600 rpm engines. See Figure
17.
MOUNTED ON
CYLINDER COVER
\
VOLTAGE
REGULATO
RECTIFIER
MOUNTED BEHIND
BLOWER WHEEL
\
VR1
VOLT
REG
RECT
AC B+ AC
TOR
TO BATTERY
CAUTION:
REGULATOR MUST BE GROUNDED
THROUGH MOUNTING BOLTS
PRESSED INTO
FLYWHEEL
(NOT REMOVABLE)
ES-1332
FIGURE 17. 15 AMP SYSTEM
30
Redistribution or publication of this document,
by any means, is strictly prohibited.
'
TESTING PHELON 15 AMP SYSTEM
BASIC TEST
I
PROCEDURE
TEST VALUES
1. Battery
Battery Voltage - unit not running.
12 VDC
2. Regulator
Battery Voltage after unit is running
3 to 5 minutes.
13.6 to 14.7VDC
__
3. Alternator Stator
and Wiring
Ohmmeter reading from stator output,
unit not running. Check at plug.
4. Alternator and
Wiring
Measure AC open circuit stator voltage
with unit running. Measure between two 28 VAC minimum
stator leads with plug disconnected and 65 VAC maximum
unit running at approximately 3600 rpm.
I
.
-
O.l-l,to rO.19-Ohms
1
I
..
..
.
.
20 AMP FLYWHEEL ALTERNATOR
SYSTEM
The 20 amp flywheel alternator systems use a separate regulator and a separate rectifier. Figure 18. Two
black wires and one red wire come from the stator
assernbly.
ALTERNATOR STATOR
MOUNTED BEHIND BLOWER WHEEL
T O TERMINAL
CONNECTOR
RECTIFIER
ASS€ MB LY
\
,,
*
pMToR
ASSEMBLY
FIGURE 18. 20 AMP SYSTEM
31
Redistribution or publication of this document,
by any means, is strictly prohibited.
TESTING ALTERNATOR
TESTING REGULATOR ASSEMBLY
For tesfing this system, use a voltmeter-ohmmeter
such as a Simpson 270. Listed below are various
alternator problems with individual test procedures
following.
To check for proper voltage regulation, attach a DC
voltmeter to battery and operate engine at approximately I800 rpm. Battery voltage will climb to
the present factory setting (14.2 to 14.8 volts). .
-
No Output Stator Assembly
Some installations may vary due to voltage drop in the length of
ammeter harnesses. Other variations may stem from a loose
connector in the harness or loose or corroded battery leads. LOW
voltage readings at the battery mean poor battery connections.
Examine 1ead.wiresfor loose or broken connectionsat
the regutator and rectifier. Use the Rxl scale on the
ohmmeter for detecting opens in the stator. Disconnect the three wires that come from alternator
stator (two black, one red). Connect ohmmeter test
leads to red leadwire and ground to check continuity.
The ohmmeter reading should be about 2.0-ohms.
See Figure 18.
To test regulator, remove connector. Using the
Rx10,OOO scale of the ohmmeter, connect one meter
lead to red leadwirearid other meter lead to regulator
base. See Figure 18. No deflection should be noted
on the ohmmeter in either polarity. Next connect
meter to black leadwire and base of regulator. Meter
will deflect fuily in one polarity, with no deflection in
the other.
Next connect meter to black leadwires and ground.
Approximately 0.1-ohm should be read from either
black lead to ground. If noconnection existsbetween'
ground and black leads, stator assembly should be
replaced.
-
Full Charge Will Not Regulate
Check for broken leads at connection to regulator
plates. To be sure regulatorwinding operates properly, connect red lead to ground and start engine. A
maximum of 4 amperes should be noted. This would
indicate stator winding is satisfactory. If so, replace
regulator.
Checking Rectifier Assembly
Examine each of the two diodes for breakdown by
connecting.ohmmeter (Rxl scale) to one black lead
and to the white lead. Meter should read 10-ohms in
proper polarity. A shorted diode would readzero resistance and would cause a short circuit through the
lead winding when in operation. An open diode
would read infinite in both directions, indicating that
replacement is necessary.
No Charge
If alternator does not charge when load is applied to
battery, shut off engine and disconnect one red
leadwire from regulator terminal. Be sure lead is
taped or isolated from conducting engine parts. Once
again, start engine. Alternator should charge to full
output; if it doesn't, replace stator assembly.
TESTING 20 AMP SYSTEM
TEST
VALUE
Battery voltaye - unit not running.
I
12 Volts DC
Battery voltage with unit running at 1800 rpm or more.
AC voltage from stator with plug disconnected and
unit running at approximately 1800 rpm.
Ohmmeter reading at plug when checking two AC
stator leads - unit not running.
1
-
14.2 14.8 Volts DC
'
I
23 VAC minimum'
.
Black to Black
0.5 to 0.7-Ohms"
Black to Black
- -- 48 VAC
**
maximum at 3600 rpm, Red to Ground.
Resistance values (Ohms) are as follows between wire pairs.
Redistribution or publication of this document,
by any means, is strictly prohibited.
32
Oil System
*
Normal oil pressure should be 30 psi (207 kPa) or
higher when the engine isatoperating temperature. I f
pressure drops below 30 psi (207 kPa) at governed
speed, inspect the oil system for faulty components.
The engine has pressure lubrication to all working
parts. The oil system includes:
I
Oil intake cup
Gear type oil pump
Oil pressure gauge
Oil passages to deliver oil throughout.
engine
Oil filter (if used)
__
OIL PUMP INTAKE CU
Crankcase pressure could blow out
hot oil and cause serious burns. Do
NOT check oil while the engine is operating.
I
)
The oil pump is located on the front surface of the
crankcase and is driven by the crank gear. The inlet
pipeand screen assemblyattach directlytothe pump
body. Figure 19. A discharge passage in the cover of
the pump registers with a drilled passage in the
crankcase. Parallel passagesdistributeoil to the front
main bearing, rear main bearing, and pressure control bypass valve.
ON LEFT SIDE +
OIL PUMP ASSEMBLY;
Circumferential grooves in the main bearings supply
oil to the connecting rod bearings through drilled
passages from each main journal.
FIGURE 19. OIL PRESSURE PUMP ASSEMBLY
OIL BYPASS VALVE
A drilled passage connects the front main bearing oil
supply to the front camshaft bearing. The flyball
governor is lubricated byadrilled passage in thefront
camshaft journal.
The by-pass valve (located to the right and behind
gear cover), controls oil pressure by allowing excess
oil to flow directly back to the crankcase. Normally
the valve begins to open about 30 psi (207 kPa).
The oil overflow from the bypass valve furnishes
lubrication to the camshaft drive gears.
The valve is non-adjustable and normally needs no
maintenance. To determine if abnormal (high or low)
oil pressure is caused by a sticky plunger inspect as
f 01lows:
1. Remove 3/8 x 24 x 3/4 cap screw located behind
gear cover and under governor arm.
2. Remove spring end plunger with a magnet tool.
Clean plunger and spring with a suitable solvent
and install.
FIGURE 20. OIL PRESSURE
33
Redistribution or publication of this document,
by any means, is strictly prohibited.
CRANKCASE BREATHER RCCK
AND MCCK (Begin Spec B)
CRANKCASEBREATHERMCCK
(Spec A Only)
These engines areequipped with a crankcasebreather for maintaining crankcase vacuum. Clean the
crankcase breather cap and valve assembly and the
breather tube baffle in a suitable solvent every 300
operational hours. To remove breather cap and valve
assembly, remove breather hose clamp and breather
tube clamp. See Figure 21.
Lift off rubber breather cap. Carefully pry valve from
cap. Otherwise, press hard with both of your thumbs
on top of cap and keep fingers below to releasevalve
from rubber cap. Wash this fabric, flapper-type check
valve in a suitable solvent. Dry and install. Position
perforated disc.toward engine. See Figure 22.
1
SREATHER HOSE
BREATHERTUBE
CAP'
FLAPPER
VALVE
ASSEMBLY
.AMF
BREATHER.
UBE B A F F L E
125i
FIGURE 22. CRANKCASE BREATHER MCCK SPEC A ONLY
FIGURE 21. CRANKCASE BREATHER
34
Redistribution or publication of this document,
by any means, is strictly prohibited.
RCCK Cooling System
.C
'
DESCRIPTION
CLEANING
The RCCK cooling system is a closed system which
uses an engine mounted pump to draw and circulate
coolant through the engine and radiator.
To clean the cooling system, drain and fill with
radiator cleaner. When chemical cleaning is done,
always flush the cooling system to wash out deposits
loosened by the chemical cleaning. Flush the engine
water jacket as previously discussed. When flushing
is completed, check the system thoroughlyfor leaks.
Water from the radiator enters the pump located on
the front 0ftheengine.Thepumpdelivers waterto the
cylinder jacket and it flows through thejacket'and out
of the cylinder heads to the radiator. The waterflow is
controlled by thermostats. For engine warm-up, with
thermostats closed, a by-pass between the cylinder
heads allows water flow.
REPAIR
When making cooling system repairs, use Permatex
or other thread-sealing compound on all threaded
connections.
MAINTENANCE
All water lines should be 1/2 inch (13 mm) inside
diameter or larger. Long runs of pipe or hose need a
larger inside diameter to reduce resistance.
Cooling system maintenance includes periodic inspection for leaks, and flushing and cleaning.
FLUSHING
Water Pump: Refer to centrifugal pump repair in
MCCK COOLING SYSTEM for repair procedures.
The cooling system must be kept clean to function
properly. Scale reduces heat transfer and restricts
water flow. Flush the system at least once a year and
more often if operation indicates clogged passages,
pump wear, or overheating.
Thermostats: A thermostat is located on the top of
each cylinder head. Replace thermostats that are
damaged from corrosion or other causes.
To flush the engine, remove both thermostats, Figure
23. Attach a flushing gun nozzle to the thermostat
opening and fill the block with water; then apply air
pressure. Repeattheprocess until watercoming from
the block is clean.
Check opening and closing by placing the thermostat
and a thermometer in heated water. The thermostat
should start to open at 175" F (70' C) and befullyopen
at 202' F (94OC). It should close immediately when
removed from hot water. Replace the thermostat if it
does not operate properly.
High Water Temperature Cut-off Switch: This normally closed switch (Figure 24) senses water
temperature in the engine cooling jacket. The switch
opens, breaking the circuit to the coil primary when
the water temperature reaches about 230" F (110" C)
and closes when the temperature drops below 190' F
(88'C).
TEMPERATURE
SWITCH '
FIGURE 23.
FIGURE 24.
THERMOSTAT REMOVAL
35
HIGH WATER TEMPERATURE SWITCH
Redistribution or publication of this document,
by any means, is strictly prohibited.
MCCK Cooling System
DESCR IPTI0N
The MCCK cooling system is a pressure type system
which uses an engine mounted rubber impellerpump
to draw and circulate raw water throughout the
system.
In open type cooling systems, water enters the pump
located on the front right side of engine. The pump
delivers water to the cylinder jacket. Water flows
through the jacket and out openings in cylinder
heads controlled by thermostats.' For engine warmup, with thermostats closed, a by-pass from the
cylinder block to the thermostat allows water flow.
From thermostat, water passes through the watercooled exhaust manifold and out engine cooling
system.
THERMOSTAT
MAINTENANCE
Cooling system maintenance includes periodic inspection for leaks, inspection of the rubber pump
impeller, and flushing and cleaning.
Confacfwifh hof coolanfmighf result
WARNING
in serious burns. Do not bleed hot,
n
@-DRAIN
As888
pressurized coolant froma closed cooling sysfem.
PLUG
FIGURE 25. THERMOSTAT REMOVAL
The rubber impeller, because of continuous flexing,
will, in time, need replacement. If impeller fails after
short service (usually under'500 hours), check for
possible defects, such as severe pitting or abrasion
caused by dirt in the cooling system.
Cooling system MUST be kept clean to function
properly. Scale reduces heat transfer and restricts
water flow. Flush system at least once a year and
more often if operation indicates clogged passages,
pump wear, or overheating.
To flush engine, remove the thermostats, Figure 25
and the water pump cover. Partially restrict pump
opening so the cylinder block fills with water. Attach
a flushing gun nozzle to thermostat opening and fill
block with water; then apply air pressure. Repeat the
process until water coming from the block is clean.
2. Air leaks will cause premature impellerfailure.To
test for air leaks, insert the cooling system outlet
into a tank of water and watch for bubbles while
engine is operating. If bubbles appear, inspect
cooling system thoroughly to find the source.
REPAIR
When making cooling system repairs, use Permatex
or other thread-sealing compound on all threaded
connections.
All water lines should be 1/2 inch or larger inside
diameter. Long runs of pipe or hose need a larger
inside diameter to reduce resistance.
THERMOSTATS
Thermostats are located on the top of each cylinder
head. These are connected by tubing to the watercooled manifold. Replace all thermostats that are
damaged (from corrosion or other causes). See Figure 25.
Check opening and closing by placingthethermostat
and a thermometer in a water bath. The thermostat
should start to open at 145OF and be fully open at
165OF: It should close immediately when removed
from hot water. Replace the thermostat if it does not
operate properly.
TESTING
Cooling system can be tested for two abnormal conditions: (1) insufficient water flow and (2) air leaks.
1. To measure water flow, install a tank of known
capacity at the water outlet. Run engine until the
thermostat opens and then measure the length of
time necessary to fill the tank. From this, obtain
the flow in gallons per minute (GPM).If water
flow is below 3.5 GPM, check pump operation
and inspect passages and water linesforclogging.
36
Redistribution or publication of this document,
by any means, is strictly prohibited.
"
.
HIGH WATER TEMPERATURE
CUT-OFF SWITCH
This normally closed switch senses water ternpera-
'
Assembly (Pump 131-0165)
Inspect the pump housing for wear, rough surfaces,
or pitting and replace if any of these conditions exist.
Replace any other worn components such as bearings, seals, or impeller and use a new end plate
gasket.
1. Apply sealing compound to thesealing lip around
the edge of the bellows seal. Place the bellows
seal in the pump body and drive it into place(Step
9)
2. Apply a small amount of Loctite or eqivalent on
the outside surface of the bearing (Step h).
3. Placethe bearing and shaft assembly in the pump
bore and drive into place (Step i). Strike outer
race only to avoid damage to pump shaft and
bearing.
4. Lubricate both sides of the seat assembly (ceramic seal and O-ring) with lubricating oil and
slide assembly over pump shaft.Theceramic portion of the seat assembly should contact the bellows. Compress the seat assembly against the
bellows and at the same time push the retaining
ring into its groove on the pump shaft.
5. Place wear plate and cam so notch in wear plate
lines up with tank on cam (Step j). Fasten cam to
housing with screw.
6. Align the flat spot in the center of the impeller
with the flat spot on the pump shaft. Bend back
the impeller blades nearest the cam and push the
impeller onto the shaft. Do not removethe factory
coating of oil from the new impeller before
installing.
7. Install the pump end plate using a new gasket and
tighten end plate screws to 15-17 in-lb (1.7-1.9
Nm).
8. Install pump on engine (Step k) and attach hoses.
ture in the engine cooling jacket. The switch opens,
breaking the circuit to the coil primary when the
water temperature reaches approximately 200°F and
closes when the temperaure drops below approximately 160" F.
WATER PUMP
-
This pump is a positive displacement, neoprene
impeller type, used to pump raw water through the
cooling system.
Disassembly (Pump 131-0165)
1. Remove the pump end plate screws, end plate,
and gasket as shown in Figure 26 (Step a).
2. Pull out neoprene impeller with a pair of pliers
(Step b).
3. If further disassembly is required, disconnect the
hoses and removethe two capscrews holding the
pump to the engine (Step c). Lift pump from
engine.
4. Loosenthe set screw on the side of the pump and
tap it lightly to free the cam from the pump body.
Lift out cam and wear plate (Step d).
5. Remove the retaining ring (using a screwdriver)
as shown in Step e and slide the seat assembly
(O-ring and ceramic seal) off the pump shaft.
6. Pry the bellows assembly out of the pump body
by inserting ascrewdriverthrough the drain slots
(Step f).
7. Drive the shaft and bearing assembly out of the
pump body using a bearing driver or press. The
bearing is press fit on the shaft and comes off in
one integral part.
37
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by any means, is strictly prohibited.
BEARINGAND
SHAFT ASSEMBLY
GASKET
ASSEMBLY
ASSEMBLY
END PLATE
PUMP
BODY
/
/
RETAINING
RING
SCREW
WEAR
PLATE
/
1
IMPELLER
CAM
826&
d.
/
e.
a
I
8260-8
FIGURE 26. PUMP 131-0165
38
Redistribution or publication of this document,
by any means, is strictly prohibited.
,
.
Disassembly (Pump 131-0257)
1. Disconnect all hoses and remove the pump from
the engine.
2. Loosen the pulley set screw and remove the pulley from the pump shaft.
3. Remove the impeller housing screws, impeller
housing, and gasket.
4. Pull the impeller out of the impeller housing.
5. Remove the wear plate from the pump housing,
using a screwdriver to pry loose the plate if
necessary.
6. Remove the external retaining ring from the
impeller end of the water pump shaft.
7. Remove the two piece seal assembly. The spring
portion of the seal is removed first. The second
portion of the seal can be loosened and removed
with a screwdriver or needle-nose pliers.
8. Remove the internal retaining ring from the drive
pulley end of the pump housing.
9. Carefully drive out the shaft and bearing assembly from the impeller end of the housing.
10. Remove the slinger from the water pump shaft.
1. Install the new slinger on the water pump shaft.
2. Install the ceramic part of the two piece seal
assembly in the pump housing. The rubber side
of the seal should be toward the bearings.
3. Coat the inside of the water pump housing and
the outside of the ball bearing races with grease.
4. Insert the water pump shaft into the pump housing, and install the internal retaining ring in the
drive pulley end of the housing.
5. Install the spring portion of the two piece seal on
the pump shaft and secure in place with the
external retaining ring.
6. Install the wear plate so that the notch in the plate
fits into the machining in the pump housing.
7. Coat the inside of the impeller housing with
grease.
8. Install the impeller in the impeller housing by
twisting it clockwise while pushing it into place.
9. While holding the gasket in place against the
pump housing, install the impellerhousingsecuring it with four screws removed during disassembly.
10. Mount the pump on the engine and attach the
hoses.
11. Align the pump drive pulley with the crankshaft
drive pulley and tighten the set screw.
Assembly (Pump 131-0257)
Inspect the impeller housing for wear, rough surfaces, or pitting and replace if any of these conditions
exist. Replace any other worn components such as
bearings, seals, or impeller and use a new impeller
housing gasket.
PUMP HOUSING
BEARINGS AND SHAFT
WEAR PLATE
IMPELLER
HOUSING
IMPELLER
I
GASKET
\
SEAL ASSEMBLY
RING
FIGURE 27. PUMP 131-0257
39
Redistribution or publication of this document,
by any means, is strictly prohibited.
AND BEARING
FIGURE 28.
CENTRIFUGAL PUMP 132-0110
Disassembly (Centrifugal Pump 132-0110)
1. Remove the water inlet fitting, drive belt pulley,
FRESH WATER
MANIFOLD
cover screws, and pump cover gasket.
2. Unscrew the threaded impeller from the pump
shaft by turning the impeller in a counterclockwise direction when facing impeller.
3. Slide the seal seat, wear face, and bellows assemblyofftheshaft. Loosentheclampscrewand
slide the pump body off the pedestal.
4. Remove the bearing lock ring and drive the shaft
and bearing assembly out of the pedestal. The
bearing is press fit on the shaft and comes off in
one integral part. The bearing is packed with a
lifelong lubricant and is sealed at each end.
E
FLAT WASHER
(WHEN USED)
Assembly (Pump 132-0110)
SALT WATER
Replace all worn components such as bearings,
seals, wear face, and impeller and use a new cover
gasket. Assembly sequence is the reverse of the disassembly procedure.
T O HEAT
EXCHANGER
PUMP
HEAT EXCHANGER
Closed-type cooling systems are commonly referred
to as fresh water cooling or heat exchanger cooling.
Water circulated throuah the enaine is called fresh
water, hot water, etc. fiater circilated through the
heat exchanger only is called raw water, sea water,
cold water, discharged water, etc. This system with
an anti-freeze coolant is recommended where freezing coditions exist, or where the owner wants to prevent the possibility of salt water or rust problems.
FIGURE 29. HEAT EXCHANGER
Maintenance: Maintain the closed water system the
Same as an automotive radiator cooling system.
Clean and flush Once a year and use anti-freeze if
there is danger of freezing. Use a rust inhibitor in the
closed water system.
The closed water system continually recirculates
captive water through the waterjacket, exhaust manifold, centrifugal pump, and one side of the heat
exchanger. Figure29 shows a typical heat exchanger.
Cleaning: To clean the closed system, drain and fill
with radiator Cleaner. When chemical Cleaning iS
done, always flush the cooling system to wash out
deposits loosened by the chemical cleaning.
Flush the engine water jacket as previously discussed. First remove the water outlet hose from the
engine water jacket to the heat exchanger. Flush both
the open and closed water system sides of the heat
exchanger. Remove the rubber impeller pump cover
to flush theopen system. Also flush thewater-cooled
exhaust manifold. When flushing is completed, check
the system thoroughly for leaks.
Do nof use the exisfing neoprene
impeller waferpumpin fhe hof wafer
side of the cooling system. Heat or soluble oil (in
many rust inhibitors and anti-freezes) will damage
the impeller. Instead, connect the neoprene impeller
pump on the cold wafer side. Use a metal impeller,
cenfrifugal-type wafer pump (Onan 732-07 70 or
equal) in ihe fresh wafer side. See Figure 28.
40
Redistribution or publication of this document,
by any means, is strictly prohibited.
.
Starting System
STARTER
’
’
.
A solenoid-shift starter is shown in Figure 30. After
the starter button is pushed, battery current energizes the start solenoid. The solenoid causes an arm
to push the starter pinion into the flywheel ring gear.
Simultaneously, the start solenoid contacts close and
allow the starter motor to start turning. The starter
remainsengaged untilthestart button is released. An
overrunning clutch protectsthe starter from damage
before it can be disengaged from the flywheel.
STARTING MOTOR
Beginning with Spec H,the starter motor on MCCK
engines is the gear drive starter shown in Figure 30a.
FIGURE 30a. GEAR-DRIVE STARTER
START BUTTON
Maintenance
For proper cranking-motor operation with a minimum of trouble, a periodic maintenance procedure
should be followed. Periodic lubrication, inspection
of the brushes, and commutator as described in this
section will insure long cranking motor life. Periodic
disassembly (see Disassembly) of the crankingmotor
for a thorough overhaul is recommended as a safeguard against accumulations of dust, grease, and
parts wear.
CLUTCH
Lubricate all oil-type bearings with 8 to 10 drops of
light engine oil (SAE 20). All oil-less type bearings
and bushings should be given afewdrops of light oil.
Lubricatethe cranking motor drives with afew drops
of light engine oil.
SHIFT ARM
SOLENOID
Never oil the commutator. Oil
cranking ability of the motor.
FIGURE 30. SOLENOID-SHIFTSTARTER
*
b
on the commutator reduces the
The commutator can be cleaned by using number 00
sandpaper. Never use emery cloth. If the commutator
is out of round or has high mica, remove it from the
cranking motor. Turn the commutator down on a
lathe being careful to remove onlyenough materialto
true up the commutator and remove high mica.
The gear drive is mounted on a shaft which extends
from the starter motor. When not running, the drive
pinion gear is retracted soit clears the flywheel ring
gear. When starting, a spiral spring through increasing speed forces the drive pinion to engage the
flywheel ring gear. The pinion and flywheel ring gear
teeth have beveled ends that ensure their engaging
properly.
It is not necessarytoundercut micaon startermotorcommutators.
Replace worn brushes. If brushes wear rapidly, check
for excessive brush spring tension and roughness or
high mica on the commutator.
Starter motors are not designed for
continuous operation. Do not operate more than 30 secondsper ON cycle. Do not operate starter more fhan70 seconds in a stall condition i f
engine will not rotate. Serious damage could result if
these time limits are exceeded.
Solenoid Shift
Periodically inspect solenoid and shift lever to make
sure they are operating properly. Keep the solenoid
shift lever free of dirt and excess grease.
41
Redistribution or publication of this document,
by any means, is strictly prohibited.
move back aslight amount againstthepressureofthe
driving spring. The longitudinal movement permits
the pinion to turn farther and enter the flywheel ring
gear.
The overrunning clutch is packed in a special high
melting point grease and after its initial assembly,
needs no further lubrication. This clutch prevents the
engine from turning the starter motor at too high a
speed once it is started. Do not subject the overrun-,
ning clutch to grease dissolving or high temperature
cleaning methods. This may cause the clutch to lose
some or all of its grease.
It is important the correct length of drive spring be used when
making replacements. The length of the drive spring controls the
longitudinal movement of the bendix pinion (meshing and
unmeshing of the pinion and flywheel ring gear).
If the pinion does not turn freely in the clutch in the
overrunning direction, or the clutch tends to slip in
the opposite direction, replace the assembly. A worn
clutch indicated by excessive looseness of the pinion
requires replacement.
Keep the drive shaft free of rust, burrs or bendssothe
drive can move freely along it. A damaged pinion
necessitates the replacement of the assembly.
’
4
Onan recommends replacement of faulty gear drive assemblies
and provides no further service information concerning their
repair. For further repair information, contact the manufacturerof
your starter motor.
Never attempt to repair or relubricate a defective clutch.
Pinion Clearance
The pinion clearance is adjusted by increasing or
decreasing the fiber washer thickness at the mounting surface of the shift solenoid.
Disassembly
1 . Remove all wires to the starting unit. Tag each
wire so it can be reconnected as originally.
2. Remove the solenoid (where applicable).
More washers decrease the clearance while less washers increase
the pinion clearance.
The clearance between the pinion and the housing
should be 0.02 to 0.08 inch (0.5 to 2 mm) when the
pinion is in the cranking position, Figure 30b.
3. Remove the starter motor thru-bolts and divide
the starter into three main assemblies- the front
bracket, the housing, and the rear bracket. On
some model starters, short screws are used to
hold the three starter sections together (Figure
31).The spacers on the solenoidstarters are used
for adjustment of the thrust gap of the armature
shaft and are located between the rear bracket
and the commutator shaft.
Drive Pinion
The teeth of the drive pinion are chamfered on only
one side and specially rounded and polished to make
the automatic meshing with the flywheel ring gear
more efficient. The drive is designed so that if the
ends of the pinion teeth meetend toend with the ring
gear teeth (keep in mind that the drive is freely
mounted on the drive shaft), the drive assembly can
On the solenoid shift models, the steel spacing washer is on
the commutator side.
flm
STARTING MOTOR
PINION GEAR
SHOULD BE BEMlEEN
0.02 to 0.08 INCH
FEELER GAUGE
(0.7” .12” CLEARANCE
SEETEXT)
-
FIGURE 30b. PINION CLEARANCES (GEAR DRIVE)
42
Redistribution or publication of this document,
by any means, is strictly prohibited.
.
THROUGH BOLTS
5. Solenoid Starter Only: Removethe ring afterdriv-
ing the pinion stopper toward the pinion gear,
using a cylindrical tool (Figure 32). Remove the
overrunning clutch and the pinion stopper at the
same time.
6. Gear Drive Starter Only: The entire assembly is
mounted on the armature shaft. When disassembling the starter, pay particular attention to the
various parts and their positioning in the starter
assembly (Figure 33). If the gears of the pinion
are damaged, replace the entire pinion. Inspect
the screw shaft for rust and burrs.
ASSEMBLY
FIGURE 31. SOLENOID SHIFT STARTER
7. Remove the brushes from the brushholder and
inspect them (inspection of brushes and brush
springs discussed later).
4. Solenoid Starter Only: The armature can now be
removed from the front bracket. Be careful not to
miss thesmall steel washer used in the end of the
armatureshaft. Removetheshiftleveratthesame
time the armature is removed. The spring holder,
lever springs, and retainer can be removed prior
to removing the lever (Figure 31a).
8. Remove the pole shoes, if necessary, by rernoving the flathead machine screws which anchor
them to the frame.
SOLENOID-SWITCH
MRU-BOLTS
i
ASS E MB LY
SHIFT
LEVER
I
r
SPRING
HOLDER
I
"z
-
ARMATURE
1
BRLISH
SPACERS
OVERRUNNING
CLUTCH
FRONT BRACKET
ASSEMBLY
FIGURE 31a. SOLENOID SHIFT STARTER.
FIELD COILS
ASSEMBLY
1
INTERMEDIATE
BEARING
PINION HOUSING
COVER BAND
FIGURE 32. TOOL FOR DRIVING PINION STOPPER
FIGURE 33. GEAR DRIVE STARTER
43
Redistribution or publication of this document,
by any means, is strictly prohibited.
Testing the Armature for Open Circuit: The most
common place for an open circuit is at the commutator riser bars. inspect conductors for loose connections at points where they are joined to the commutator bars.
ELECTRIC STARTER INSPECTION AND
TROUBLESHOOTING
Testing the Armature for Shorts: Place the armature
in the growler and hold a thin steel blade parallel to
the core and just above it, while slowly rotating the
armature in the growler (Figure 34). A shorted armature causes the blade to vibrate and move toward the
core. A shorted armature must be replaced.
Testing Commutator Runout: Place the commutator
on a test bench and check runoutwith adial indicator
(Figure 36). When commutator runout exceeds 0.004
inch, reface the commutator.
,
d
FIGURE 34. TEST FOR SHORTED ARMATURE
FIGURE 36. CHECKING COMMUTATOR RUNOUT
Testing Armature for Grounds: Touch armatureshaft
or core and the end of each commutator bar with a
pair of ohmmeter leads (Figure 35). If the ohmmeter
reading is low, it indicates a grounded armature.
Replace a grounded armature.
Testing Armature Shaft Runout: The armature shaft
as well as the commutator may be checked. A bent
armature can often be straightened, but if the shaft is
worn a new armature is required (Figure 37).
FIGURE 37. CHECKING ARMATURE SHAFT RUNOUT
Testing Field Coils for Grounds: After unsoldering
the shunt field coil wire, place one test prod on the
connectorand the other on a clean spot on the frame.
If the ohmmeter indicates continuity, the fields are
grounded either at the connector or in the windings
(Figure 37a).
FIGURE 35. TEST FOR GROUNDED ARMATURE
44
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by any means, is strictly prohibited.
4
.28"
RCCK
MCCK
FIGURE 39. BRUSH WEAR LIMITS
Inspection for Brush Spring Tension: Measure brush
spring tension with a tension meter (Figure 39a).
Push the brush into its holder and take the reading
just as the brush slightly projects from the brushholder. On a new brush thespring tension should be
49 to 59 ounces (1.37-1.65 kPa) for RCCK engines
and 29 to 38 ounces (0.81 to 1.06 kPa) for MCCK
engines.
ONE PROD ON FIELD COIL
LEAD. ONE PROD ON FRAME.
FIGURE 37a. FIELD COIL GROUND TEST
Testing Field Coilsfor Open Circuits: Place one prod
on the connectorand the other on a clean spot on the
brushholder (Figure 38). If continuity is good, the
field coil is good. Check all brushholders in the same
manner.
FIGURE 39a. MEASURING BRUSH SPRING TENSION
Assembly: Reassembly is much the reverse of disassembly procedure. Follow these precautions and
procedures:
1. Cleanall partscarefullywithadryclothandcompressed air if available.
Do not immerse bearing equipped parts in cleaning fluid.
Clean wifh a brush dipped in mineral spirits.
Donof clean overrunningclufch
in solvenf or liquid cleaning
solufion. Washingthe clufch will cause the grease
to leak out.
ONE PROD ON FIELD COIL LEAD
ONE PROD ON BRUSH HOLDER.
SHOULD LIGHT.
2. Apply20 weightoil to armatureshaftandsplines.
Use grease sparingly on solenoid starter shift
lever pin, joint of shift lever and plunger, plunger
and spacing washers at end of the shaft.
3. Use spacing washers to adjust armature end play
of 0.004 to 0.020 inch (0.102 to 0.508 mm).
4. When assembling starter to engine oil base, do
not draw the mounting bolts up tight. The gears
should have 0.004 to0.007 inch backlash. Tap the
starter in or out from the oil base to adjust. Then
tighten starter mounting bolts to 30 ft.-lb. (41
Nm).
FIGURE 38. TEST FOR OPEN FIELD COIL
inspection of Brushes: When brushes are worn more
than 0.3 inch, replace them. Figure39showsthe wear
limit. See that the brushes move smoothly in the
brushholders.
45
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Engine Disasse.mbly
4
If engine disassembly is necessary, first remove all
the. complete assemblies (e.g. manifold with carburetor and vacuum speed booster). Individual
assemblies, as the carburetor, can be removed and
serviced later, if necessary. Follow the general disassembly steps given below and refer to the appropriate detailed instructions in this section. When
reassembling; check the text for special assembly
instructions.
6. Install crank gear aligning timing mark with mark
on camshaft gear.
7. Install valve assemblies and cylinder heads.
8. Install gear cover and oil seal.
9. Install flywheel.
10. Install fuel pump, manifold assembly, air cleaner,
.. fuel lines, spark plug, breaker box, etc.
1
11. Connect electrical wires, exhaust line and
battery.
12. Fill crankcase with proper oil.
.
...
Keep alt parts in their respective order
valve
assemblies,. rod caps for respective rod and piston
assemblies, etc. Analyze reasons for parts failures.
Use new gaskets for assembly.
FLYWHEEL
To remove the flywheel, turn the flywheel mounting
screw outward about two turns and use Onan puller
420-0100 to pull the flywheel, Figure 40.
GENERAL DISASSEMBLY
~~
1. Drain crankcase oil.
2. Disconnect exhaust pipe7fuelline,
and electrical connections.
3. Remove flywheel using Onan flywheel puller.
4. Remove gear cover using care to protect oil seals
from keyway damage.
5. Remove snap ring and remove crankshaft gear
using a gear pulling ring and gear pulter.
6. Remove air cleaner, manifold assembly (with
carburetor and vacuum speed booster), fuel
pump, fuel lines, spark plugs, ignition breaker
box, etc.
7. Remove cylinder heads, oil base and oil pump.
8. Remove valves, springs, tappets, etc.
9. Remove camshaft and gear assembly.
t 0. Remove connecting rods, pistons and bearings.
11. Remove rear bearing plate.
12. Remove crankshaft.
13. Remove bearings as needed using correct bearing remover.
Do not drop the flywheel. Always use astee1 key for
mounting the flywheel.
FIGURE 40. ONAN FLYWHEEL PULLER
GEAR COVER
After removing the flywheel key and mounting
screws, tap the gear cover gently with a soft-faced
hammer to loosen it.
GENERAL ASSEMBLY
Engine assembly usually is the reverse of the disassembly procedure. Use a torque wrench whenever
possible and observe proper clearances throughout
assembly. Coat all internal parts with oil. During
assembly, turn engine over by hand - should turn
over freely.
1. Install new main bearings, if required, using
proper bearing driver.
2. Install crankcase and rear bearing plate (check
end play).
3. Install pistons, rods, bearings and rod caps.
4. Install crankshaft and timing gear assembly.
5. Install oil pump and oil base.
installing the gear cover, make
E3
sure that roll pin in fhe gear
engages fhegovernor
correctly. Figure
When
cup
cover
41.
Turn the governor cup so that the plastic bushed hole
is at the three o’clock position. Thesmooth side of the
governor yoke must ride against the governor cup.
Turn the governor arm and shaft clockwise as far as
possible and hold in this position until thegear cover
is installedflush against the crankcase. becareful not
to damage the gear cover oil seal. Adjust the roll
(stop) pin to protrude to ajoint 3/4 inch from the cover
mounting surface. See Figure 41.
46
Redistribution or publication of this document,
by any means, is strictly prohibited.
b
.(
~VRNOR
CUP
OVERNOR ARM
ROLL P
GOVERNOR SHAFT
ROTATE
GOVERNOR CUP
SO THAT ROLL PIN'
FITS INTOTHE
HOLE IN PLASTIC
BUSHED CUP.
GOVERNOR
SHAFT YOKE
FIGURE 41. GEAR COVER ASSEMBLY
GOVERNOR CUP
I
IF FEELEW WILL
ENTER H O E 1
0 (13 mn).
BALL H M FALLEN OUT
cup and snap ring on the center pin, Figure 42.
With thegearcover removed, thegovernorcup can be
taken off after removing the snap ring from the
camshaft center pin. Catch the flyballs while sliding
the cup off. See Figure 41.
The camshaft centerpin extendsout 3/4inchfromthe
end of the camshaft. This distance provides and in
and out travel distance of 7/32inch for the governor
cup, as illustrated. Hold the cup against the flyballs
when measuring. If the distance is less (the engine
may race, especially at no load), remove the center
pin and press a new pin in only the required amount.
otherwise, grind off the hub of the cup as required.
The camshaft center pin cannot be pulled outward
nor removed without damage. If the center pin .
extends out too far, the cup will not hold the flyballs
properly.
Replace any flyball that is grooved or has aflat spot. If
the arms of the ball spacer are worn or otherwise
damaged. replace the entire timing gear set. The
governor cup must spin freely on thecamshaft center
pin without excessive loosenessor wobble. If the race
surface of the cup is grooved or rough, replace it with
a new one.
When installing the governor cup, tilt the engine so
the gear is up, put the flyballs in placeand install the
TIMING GEARS
If replacement of either the crankshaft gear or the
camshaft gear becomes necessary, install both gears
new, never one only. Use agear pulling ring to remove
the crankshaft gear. Be sure to remove the snap ring
first.
WHEN GOVERNOR
IS PROPERLY
ASSEMBLED THE
DIMENSION SHOWN
ON DRAWINGWILL
BE AS INDICATED.
The camshaft gear is pressed on and keyed to the
Camshaft. The camshaft and gear must be removed as
an assembly after first removing the crankshaft gear
lock ring and washer. Before removing the camshaft
and gear assembly, remove the cylinder head and
valve assemblies. Remove the operating plunger for
the breaker points. Remove the fuel pump and
tappets.
CENTER PIN
The camshaft may be pressed out of the gear by use of
a hollow tool or pipe which will fit over the camshaft
center pin. Do not press on thecenter pin or damage it
in any way. The governor ball spacer is a press fit to
the camshaft gear.
GOVERNOR CUP
GOVERNOR FLYBALL
When pressing a camshaft gear onto the camshaft, be
sure the gear is started straight and that the key is
properly in place. Install the governor cup assembly
before installing the camshaft and gear in the engine.
88
FIGURE 42. GOVERNOR CUP
47
Redistribution or publication of this document,
by any means, is strictly prohibited.
I
FIGURE 43. TIMING GEAR REMOVAL AND INSTALLATION
Each timing gear is stamped with an "0"mark near
the edge. The gear teeth must mesh so that these
marks coincideexactly when thegears are installed in
the engine, Figure 43. Be sure, when installing the
camshaft gear and shaft assembly, that the thrust
washer is properly in place behind thecamshaftgear.
Replace the camshaft retaining washer and lock ring
to the crankshaft.
CYLINDER HEADS
The cylinder head should be tightened in the order
designated per Figure 44to a torqueof 5foot-pounds
(6.8 Nom), then 10 foot-pounds (13.5N.m). etc. until
all are torqued to 29 to 31 foot-pounds (39-42Nom).
VALVES
FIGURE 44. CYLINDER HEAD BOLT TORQUE SEQUENCE
Properly seated valves are essential to good engine
performance. The cylinder head is removable for
vaiveservicing. Do not use apry to loosen the cylinder
head. Rap sharply on the edge with a soft-faced
hammer, taking care not to break any cooling fins. A
conventional type valve spring litter may be used
when removing the valve spring locks, which are of
the split type. Clean all carbon deposits from the
cylinder head, pistontop, valves, guides, etc. If avalve
face is burned or warped, or the stem worn, install a
new valve.
Worn valve stem guides may be replaced from inside
the valve chamber. See Figure 45. A seal is provided
behind the intake valve guides only. The smaller
diameter of the tapered valve guides must face toward
the valve head.
Tappets are atso replaceablefrom thevalve chamber,
after first removing the valve assemblies.
NOTE SEE VALVE T A P P E T
CLEARANCES IN TEXT
VALVE RETAINE
FIGURE 45. VALVE SYSTEM
48.
Redistribution or publication of this document,
by any means, is strictly prohibited.
TAPPET ADJUSTMENT
The engine is equipped with adjustable tappets. To
make a valve adjustment, remove the valve covers.
Crank the engine over slowly by hand until the left
hand intake valve. when facing the flywheel, opens
and closes. Continue about 1/4 turn until the correct
timing marks align. This should place the left hand
piston at the top of its compression stroke, the
position it must be in to get proper valve adjustment
for the left hand cylinder. Clearances are shown in
DIMENSIONS AND CLEARANCES section. For each
valve. the gauge should just pass between the valve
stem and valve tappets (Figure 47).
INTAKE AND EXHAUST VALVES
(SEE TABLE O F CLEARANCE
FIGURE 46. VALVE FACE AND
SEAT ANGLES
The valve face angle IS 44 degrees. The valve seat
angle is 45 degrees. This 1 degree interferenceangle
results in a sharp seating surface between the valve
and the top of the valve seat. The interference angle
method of grinding valves minimizes face deposits
and lengthens valve life, Figure 46.
The valves should not be hand lapped, if at all
avoidable, since the sharp contact may be destroyed.
This is especially important where chromecobalt
faced valves and seats are used. Vaive faces should be
finished in a machine to 44 degrees. Valve seats
should be ground with a 45 degree stone and the
width of theseat bandshould be 1/32to3/64(0.79-1.2
mm) of an inch wide. Grind only enough to assure
proper seating.
:
'
FIGURE 47.
TAPPET ADJUSTMENT
To correct the valve clearance, turn the adjusting
screw as needed to obtain the right clearance. The
screw is self-locking.
To adjust the valves on the right hand cylinder. crank
the engine over one complete revolution and again
line up the correct timing marks. Then follow the
adjustment given for the valves of the left hand
cylinder.
Remove all grinding compound from engine parts
and place each valve in its proper location. Check
each valve for a tight seat, using an air pressure type
testing tool. If such a tool is not available, make pencil
marks at intervals across the valve face and observe if
the marks rub off uniformly when the valve is rotated
part of a turn against the seat.
PISTON AND RINGS
Whenever there is a noticeable wear ridge at the top of
each cylinder, remove the ridge with a ridge reamer
before removing the pistons. If not. the rings can
catch the ridge when pushing out the pistons and
cause a ring land fracture, Figure 48.
Lightly oil the valve stems and reassemble all parts
removed. Adjust the valve clearance (see Tappet
Adjustment j.
The positive type valve rotocoils serve to prolong
valve life and decrease valve repairs. Check the
rotocoils periodically by removing the cylinder heads
and cranking the engine. When functioning properly,
the valve is rotated a fraction of a turn each time it
iopens. If rotocoils are faulty, install new ones.
To remove the piston and connecting rod assemblies,
turn the crankshaft until a piston is at the bottom of
the stroke. Remove the nuts from the connecting rod,
bolts. ILift the rod bearing cap from the rod and push
the rod and piston assembly out the top of the
49
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by any means, is strictly prohibited.
cylinder with the handle end of a hammer. Be careful
not to scratch the crankpin o r the cylinder wall when
removing these parts.
CY Ll N D E R
4
Keep the connecting rod bearing caps and bearings
with their respective rods.
#
The pistons are fitted with two compression rings and
one oil control ring with a n expander. Remove these
rings from the piston using a piston ring spreader.
Clean the piston ring grooves with agroove cleaner o r
the end of a broken ring filed to a s h a r p point, Figure
49. All passages should be cleaned with a non-caustic
solvent. Clean the rod bores and t h e back of the
connecting rod bearings thoroughly.
REMOVING P I S T O N WITH LARGE WEAR
RIDGE COULD BREAK RING OR RING LAND.
Mark each piston to make sure t h e rod will be
assembled on the piston from which it was removed.
Remove t h e piston pin retainer from each side and
push the pin out.
FIGURE 48. WEAR RIDGE ON CYLINDER WALL
Inspect the pistons for fractures at t h e ring lands,
skirts and pin bosses. Check for wear at t h e ring land
using new rings and a feelergauge as shown in Figure
50. See DlAdENSlONS AND CLEARANCES section
for proper side clearance measurement and ring .
groove widths.
1
FIGURE 49. CLEANING PISTON RING GROOVES
FIGURE 50. INSPECTING RING LANDS
50
Redistribution or publication of this document,
by any means, is strictly prohibited.
Rings which are slightly oversize may be filed as
necessary to obtain the correct gap, but do not use
rings which require too much filing. Standard size
rings may be used on 0.005 inch oversize pistons.
Other oversize rings must be used with corresponding oversize pistons. Rings of the tapered type are
usually marked top on one side, or identified in some
other manner and the ring must be installed with this
mark toward the closed end of the piston.
CYLINDER
WALL
Space each gap one third of the way around the
piston from the preceding one, with no gap directly in
line with the piston pin. The bottom piston ring groove
should be fitted with an expander and an oil control
ring and the two upper grooves fitted with compression rings. If a chrome faced ring is used, it will be in
the top groove. Theoil control ring is selected for best
performance in regard to the correct unit pressure
characteristics.
FIGURE 51. NEW RING IN WORN PISTON RING GROOVE
Improper width rings or excessive ring side clearance
can result in ring breakage. New rings in worn ring
grooves do not have good cylinder wall contact,
Figure 51.
The piston is fitted with a full-floating type piston pin.
The pin is kept in placeby two lock rings in the piston,
one at each side. Be sure these lock rings are properly
in place before installing the piston and connecting
rod in the engine. Refer to DIMENSIONS AND
CLEARANCES section for the correct piston-tocylinder clearance.
Replace pistons showing signs of bad scoring or
burring, excessive skirt clearance, wavy or worn ring
lands, fractures or damage from detonation. Replace
piston pins showing fractures, scored bores or bores
out of round more than 0.002 inch (0.051 mm).
CONNECTING RODS
The connecting rods should be serviced at the same
time the pistons orrods are serviced. Rods must be
removed with the piston. Replaceable bushings and .
bearings are used.
Use a new piston pin to check the pin bushing in the
connecting rod for wear. The clearance should be as
shown in DIMENSIONSAND CLEARANCESsection.
Proper clearance is obtained by replacing the pin
bushing and the bearings. The rod bearings are
precision size and require no reaming.
Before installing new rings on the piston, check the
ring gap by placing each ring squarely in its cylinder
at a position correspondingto the bottom of its travel
(Figure 52). The gap between the ends of the ring is
given in DlMENSlONSAND CLEARANCES section.
Install the connecting rods and caps with raised lines
(witness marks) aligned and with the caps facing
toward the oil base. The rod and cap numbered 2 fits
on the crankshaft journal nearest the bearing plate.
Coat the crankshaft journal bearing surfaces with oil
before installing the rods. Crank the engine by hand
to see that the rods are free. If necessary, rap the
connecting rod cap screws sharply with a soft-faced
hammer to set the rod square on the journal.
.
Checking Bearing Clearance With Plastigage: Make
certain that all parts are marked or identified so that
they are reinstalled in their original positions.
PISTON .RING IN
CY LlNDER BORE
Place a piece of correct size Plastigage in the bearing
cap the full width of the bearing insert about 1/4 inch
(6.35 mm) off center, Figure 53.
FEELERGAGE
Rotate the crank about 30 degrees from bottom dead
center and reinstall the bearing cap.Tighten the bolts
to the torque specified in the ASSEMBLY TORQUES
section. Do not turn the crankshaft.
Remove the bearing cap. Leave the flattened
FIGURE 52. FITTING PISTON RINGS TO CYLINDER
51
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6. Reading A compared to C and reading B compared to D indicates whether or not the cylinder is
out of round.
If cylinder is out of round 0.002 inch (0.051 mm),
rebore and hone cylinders for next oversize
piston.
FIGURE 53. MEASURING BEARING CLEARANCE WITH
PLASTIGAGE
Plastigage on the part to which it has adhered and
compare the widest point with thegraduations on the
Plastigage envelope to determine bearing clearance.
CYLINDER BLOCK
inspection:
1. Make a thorough check for cracks. Minute cracks
may be detected by coating suspected area with a
lL7Z,.
k
oil. percent
Wipe thekerosene
part dry and
andimmediately
75 percent
mixture
light
motor
of 25
apply a coating of zinc oxide (white lead) dissolved in wood alcohol. If cracks are present, the
white coating will become discolored at defective
area.
2. Inspect cylinder bore for scoring. Check Welsh
plugsfora tight, even fit and the finsfor breakage.
3. Check cylinder bore for taper, out of round and
wear with a cylinder bore gauge, telescopegauge
or inside micrometer, Figure 54. These
measurements should be taken at four places near top and bottom of piston ring travel.
4. Referring to Figure54, measurecylinderdiameter
and record the readings as follows:
a. Measure reading A across top of cylinder
where greatest piston ring wear occurs.
b. Measure reading B across cylinder at bottom
of piston ring travel.
c. Measure reading C across top of cylinder
where greatest ring wear occurs.
d. Measure reading D across cylinder at bottom
of piston ring travel.
5. Compare reading A with reading B,then compare
reading C with reading D to determine cylinder
taper due to wear.
If taper exceeds 0.005 inch (0.127 mm), rebore
and hone cylinder to accommodate the next
oversize piston.
.\
TOP END OF CYLINDER
8418
BOTTOM OF RING TRAVEL
FIGURE 54. CYLINDER BORE MEASUREMENT
52
Redistribution or publication of this document,
by any means, is strictly prohibited.
8. Clean cylinder block thoroughly with soap, water
and clean rags. A clean white rag should not be
soiled on the wall after cleaning is complete.
Never use gasoline or commercial cleaners to clean cylinder
bores after degiazing or honing. These solvents
will not remove abrasives from the walls. Abrasives not removed from engine will rapidly wear
rings, cylinder walls, and bearing surfaces of all
lubricated parts.
L
Y
9. Dry crankcase and coat it with oil.
I
.I
FIGURE 55. HONING CYLINDER
HONING PROCEDURE
1. A hone can be used to rebore a cylinder, Figure
55. Remove stock to 0.002 inch (0.051 mm) less
than finished bore with coarse hone (100 grit),
then complete honing with finish hones (300grit).
Anchor
block solidly foreither vertical or horizon2.
tal honing. Use either a drill press or heavy-duty
drill which operates at about 250. to 450 rpm.
3. Lower hone into cylinder until it protrudes 1/2 to
3/4 inch (13 to 19 mrn) past end of cylinder. Rotate
adjusting nut until stones come in contact with
cylinder wall at narrowest point.
AVOID THIS FINISH
4. Loosen adjusting nut until hone can be turned by
hand.
5, Connect drill to honeand start drill. Move hone up
and down in the cylinder about 40 cycles per
minute. Usually the bottom of the cylinder must
be worked out first because it is smaller. When
cylinder takes a uniform diameter, move hone up
and down all the way through the bore. Followthe
hone manufacturer’srecommendationsfor wet or
dry honing and oiling the hone.
6. Check diameter of cylinder regularly during honing. A dial bore gauge is the easiest method but a
telescoping gauge can be used. Check the size at
six places in the bore: measure twice at the top,
middle and bottom at 90 degree angles.
I . When the cylinder is about 0.002 inch (0.051 mm)
within the desired bore, change to finestones and
finish the bore. The finish should not be smooth
but as shown in Figure 56. The crosshatch formed
by the scratching of the stones should form an
angle of 23 degrees. This can be achieved by
moving the hone up and down in the cylinder
about 40 cycles per minute.
-
PRODUCE CROSS HATCH SCRATCHES
FOR FAST RING SEATING
FIGURE 56. CORRECT HONE FINISH
53
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by any means, is strictly prohibited.
installation. Coat the bearing with lubricating oil to
reduce friction. Place the bearing on the crankcase
over the bearing bore with the lubricating hole (front
only) in proper position. Be sure to start the bearing
straight. Press the front bearing in flush with the
outside end of the bearing bore. Press the rear
bearing in until past the ignition plunger hole.
PRECISION TYPE
Do not line ream
or bore.
--------- -----.---ALIGN HOLE IN BEARING
WITH HOLE IN BEARING BORE
CAMSHAFT BEARING
Crankshaft
New crankshaft, main bearings are precision type
which do not require line reaming or line boring after
installation. Before putting in the main bearings,
expand the bearing bore by placing the casting in hot
water or in an oven heated to 2OOOF (93OC).If
practical, cool the precision bearing to shrink it.
. OIL HOLES I N BEARING BORE
1
LOCK PIN
For putting in either the front or rear main bearing,
using instructions following, always align the oil
hole(s) in the bearing bore. Theoil passage must beat
least half open. The cold oiled precision bearing
should require only light taps to position it. Installthe
bearing flush with the inside end of the bore. If the
head of a lock pin is damaged, use side cutters or
"Easy-Out'' tool to remove pin. Then install a new lock
pin. Apply oil to the thrust washers to hold in place
when thecrankshaftisinstalled.Theoi1groovesinthe
thrust washer bearing must face the crankshaft. Be
sure two notches fit over lock pins.
BEARING
CRANKSHAFT BEARING
FIGURE 57. INSTALLATION OF CAM AND CRANKSHAFT
BEARINGS
BEARINGS
Removal of the camshaft or crankshaft bearings
requires complete disassembly of the engine. Use a
press or a suitable plug to remove the bearings.
Support the casting to avoid distortion and avoid
damaging the bearing bore during removal and
installation. Use oil on the bearings to reduce friction
when installing and again lubricate with oil after
installing. See Figure 57. Use combination bearing
driver to install the camshaft bearings.
OIL SEALS
The bearing plate must be removed to replace its oil
seal. Drive the oil seal out from the inside using a
bearing plate driver and gear cover driver. See Special
Tools section.
Camshaft
Before installing the seals, fill the space between
sealswithafibrousgreaseorstiff cup grease.Thiswil1
improve sealing. See Figure 58.
Replacement camshaft bearings are precision type
which do not require line reaming or line boring after-
. Use heavy
fiber or
cup .grease in
between seal
improve seal.
1
MOUNTING FACE
OF GEAR COVER
GEAR COVER
OIL
SEAL^ /4
THIS SURFACE SHOULD BE
CLEANED OF A L L OLD
SEALING COMPOUND BEFORE INSTALLING SEAL.
I - 1/32'' (26.2 mrn)
A877
REAR BEARING PLATE
THIS SURFACE SHOULD BE
CLEANfD OF A L L OLD
SEALING COMPOUND BEFORE INSTALLING SEAL.
GEAR COVER O!L SEAL
DRIVE OR PRESS OIL
SEAL TO SHOULDER
OFTHEPLATEBORE
REAR BEARING PLATE
OIL SEAL
FIGURE 58. GEAR COVER AND REAR BEARING PLATE OIL SEALS
54
Redistribution or publication of this document,
by any means, is strictly prohibited.
I
"
When installing the gear cover oil seal, tap the seal
inward until it is 1-1/32 (26.2 mm) of an inch from the
mounting face of the cover.
t
L
When installing the bearing plate oil seal, tap the seal
into the bearing plate bore to bottom against the
shoulder in the plate bore. Use a seal expander. or
place a piece of shim stock around the end of the
crankshaft when replacing the bearing plate to avoid
damaging the seal. Removethe shim stock as soon as
the plate is in place.
W U R E ENDPLAY
CRANKSHAFT ENDPLAY
(Refer to Table of
Clearances)
After the rear bearing end plate has been tightened
using the torque recommended in ASSEMBLY TOROIIES section, check the crankshaft endplay as
shown in Figure 59. If there is too much endplay (see
DIMENSIONS AND CLEARANCES section for
minimum and maximum endplay). remove the rear
bearing end plate and replace the gasket with a
thinner gasket from the gasket kit. For too little
endplay. remove the rear bearing end plate and
replace the gasket with a thicker one. Reinstall the
end plate making sure the thrust washer notches line
ap with the lock pins. Torque and recheck endplay of
the crankshaft.
FIGURE 59. MEASURING CRANKSHAFT ENDPLAY
OIL PUMP
Check the oil pump thoroughly for worn parts. Oil the
pump to. prime it before reinstalling. Except for
gaskets, the component parts of the pump are not
available individually. The suction cup is available
separately. Install a new pump assembly, if required.
55
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by any means, is strictly prohibited.
Wiring Diagram
LEGEND
......................................
SPARK PLUGS
............................................... STARTER
BTl .............................................. BATTERY
S1' ........................................
START SWITCH
S2' .....................................
IGNITION SWITCH
S3 ....................................... BREAKER POlNTS
T I .........................................
IGNITION COIL
T81... ..................................
TERMINAL BOARD
- CUSTOMER SUPPLIED.
El, E2
81
*
8317
FROM STARTER
SOLENOID TERMINALS
TI
El
BATTERY IGNITION SYSTEM
56
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by any means, is strictly prohibited.
Redistribution or publication of this document,
by any means, is strictly prohibited.
Cummins Power Generation
1400 73rd Avenue N.E.
Minneapolis, MN 55432
763-574-5000
Fax: 763-574-8087
Cummins and Onan are registeredtrademarksof Cummins Inc.
Redistribution or publication of this document,
by any means, is strictly prohibited.
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