Cuyuna engine Service Manual

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Cuyuna
Service Manual
Electric Start
Section
General - Magneto lgnition Theory ............. 62
Magneto Alternator System... .62-63
Capacitor Discharge Ignition Thecry —. ... ‚. 63-64
Point [gnition - Specifications ... .. 11111200 64
C.0.1. ignition - Specifications .. ...... ... ... 64
Ignition Cail Resistance Test .. .......... .. 65
ignition Generator Coil Resistance Test ... ....66
Condenser Test ... 06
Spark Plug Gap Resistance Test ............ 66
ignition Points Resistance Test... 0. 87
Charge Coil Resistance Test . 111122 210200 67
ignition Points Replacement . .. ....... .67-68
Condenser Replacement ©... 68-69
Point Igniticn Timing Procedure ..... o 69-70
Troubleshocting C.D.I. 2111114 . 70
Igrition Switch Test. TA
Ignition Ground Test 11111100 A
Spark Plug Gap Test 1 2222040 A
External Coil Resistance Test. 1. 21 71-72
Charge Coil Resistance Test 1.211 - T2
Trigger Coil Resistance Test 111 21 111 — 72
Lighting Coll Resistance Test o 72
Checking ignition Timing (C.D.i.) . . ....... 72-73
C.0.!. Diagnostic Test Procedure .. 1 121200 74
Magneto Point Ignition Test Procedure . 75
Wiring Diagram - Single Cylinder Point ignition ‚76
Wiring Diagram - Twin Manual Start Point Ignition 77
Wiring Diagram - Twin € Single C.O.1.
with Electric Start =... Co 78
Troubleshooting... - 79
61
General -
Magneto Ignition
The Cuyuna two-cycle engine electrical system con-
sists of two, somewhat separate. systems; the ignition
system and the magneto alternator system. Electrical
current for both systems is produced by the flywheel
magneto generator assembly,
The flywheel magneto generator assembly, consists
of the components listed below:
Flywheel w/imagnets
Base plate
Lighting coil
Generator coil
Breaker points
Condenser
Felt lubricator
External coil
Spark plug
CENA WN
Another component that functions in the ignition
system is the ignition switch.
IGNITION COIL (STATOR)
CONDENSER
1H
POINTS
ENGINE CONNECTOR
CUYUNA SERVICE MANUA
Magneto Alternator
System - Ignition
The magneto alternator system produces current that
provides the spark necessary to ignite the fuel/air mix-
ture in the combustion chamber. and also, current
which allows for operation of the lights and electrical
accessories. To produce and control the necessary
voltage required for ignition, a number of electrical
components are used in conjunction with each other.
FLYWHEEL-MOUNTED PERMANENT MAGNETS
Provide a moving magnetic field when the flywheel is
rotating around the generating coil and lighting coils.
CONDENSER
—
dr
SPARK PLUGE
Blue/Red 15
EXTERNAL IGNITION COILS
15
= SPARK PLUG]
IGNITION SCHEMATIC
General -
Magneto Ignition
The Cuyuna two-cycle engine electrical system con-
sists of two, somewhat separate. systems; the ignition
system and the magneto alternator system. Electrical
current for both systems is produced by the flywheel
magneto generator assembly.
The flywheel magneto generator assembly, consists
of the components listed below:
Flywheel w/magnets
Base plate
Lighting coil
Generator coil
Breaker points
Condenser
Felt lubricator
External coil
Spark plug
О 99 а О) сл А ео по
Another component that functions in the ignition
system is the ignition switch.
IGNITION COIL (STATOR)
CONDENSER
1
POINTS
ENGINE CONNECTOR
CUYUNA SERVICE MANUA
Magneto Alternator
System - Ignition
The magneto alternator system produces current that
provides the spark necessary to ignite the fuel/air mix-
ture in the combustion chamber, and also, current
which allows for operation of the lights and electrical
accessories. To produce and control the necessary
voltage required for ignition, a number of electrical
components are used in conjunction with each other
FLYWHEEL-MOUNTED PERMANENT MAGNETS
Provide a moving magnetic field when the flywheel is
rotating around the generating coil and lighting coils.
CONDENSER
нь -
= |
BluelRed 15
EXTERNAL IGNITION COILS
15
1
= SPARK PLUG]
T
IGNITION SCHEMATIC
SPARK PLUGE
oe:
НЫЙ сд
CUYUNA SERVICE MANUAL
the SCR switch is closed or triggered by a puise from
the pulser coil. The position of this pulser coil, in rela-
tion to the magnets and the piston, triggers the SCR at
the precise moment to ensure the most efficient com-
bustion. When the SCR switch closes, a circuit is com-
pleted from the capacitor to the ignition coll primary.
As a result, current flows through the external ignition
coil primary.
“IA |
SECONDARY PRIMARY
(NITION | | e i
SWITCH ee — |
sox J
pri
| |
CAPACITOR | |
i |
RECTIFIER
PULSING COIL | ;
A
SX
EXCITING +
COIN y
|
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(A meeceeees ce
MAGNETO
As previous'y stated, the external ignition coil is made
of two separate windings; a low voltage “primary”
and high voltage “secondary”. As current fiows
through the ‘primary’ the magnetic field builds up,
resulting in the induction of the “secondary”.
Because of the required high voltage current that is
needed to jump the air gap between the center and
side electrodes of the spark plug, a considerable in-
crease in voltage must take place.
But how is this increase in voltage generated? The
wire turn ratio of the secondary is considerably more
thar that of the primary, which accounts for the in-
creased secondary output. Because the secondary
has a high voltage output, it is wound above the
primary, which prevents a short circuit of the coil.
Because the secondary is wound above the primary,
the magnetic force lines of the primary are broken,
resulting in the induction of an eletromotive force
(EMF) in the secondary.
Therefore, the secondary allows high voltage current
to flow to the spark plug and jump the alr gap between
the center and side electrode. At the moment of
spark, the compressed fuel/air mixture in the combus-
tion chamber is ignitied, causing expansion and a
single power pulse.
The timing of the ignition spark, as previously stated,
is accomplished by a trigger impulse to the CDI unit
and SCR switch. The trigger impulse is induced in the
pulser coil by the flywheel magnets. The SCR requires
a certain voltage to actuate it. At cranking speeds and
low RPM there is enough voltage to actuate the SCR
when the piston is a few degrees before top dead
center (BTDC). Advancing the timing by electronic
means insures easy starting and maximum efficiency
at high BPM. The most important advantages of CDI
are: stronger ignition at cranking speeds, no
maintenance requirements of breaker points, and
simpler adjustment of timing. These result in easier
starting, peak performance and low maintenance.
Other components that function in the ignition
system, but are not mounted on the engine, Include:
the ignition switch. The ignition is calleda “closed cir-
cuit’ CDI system. This means the circuit must be
complete between the yeliow/black ignition wire and
ground, using a switch, before the igntion will func-
tion.
Point Ignition - Specifications
Description - Part Number Resistance Test Test Connections
Ignition Coil-Primary 000-43-056-060 | 1.9 ohms = 10% (+) Blue term. (—) Ground
Ignition Coil-Secondary 000-43-056-060 | 5100 ohms + 15% (+) High Ten Lead ( —) Ground
Generating Coll 000-43-211-000 | 3.7 ohms + 7% (+) Black { —) Black
Lighting Coil-30 watt 000-43-207-000 | 2.2 ohms € 10% ( +) Green (—) Green/Black
Lighting Coll-120 watt 000-43-206-000 | 1.5 ohms + 10% (+) Yellow (— ) Yellow/Black
Points 000-43-062-240 1 ohm (+) Blue-Blue/Red ( —) Ground
Condenser 000-43-065-160 | Open (+) Terminal ( —) Case
Spark Plug Cap 002-44-224-200 1000 ohms + 10% (+) Plug Term. End (—) Wire End
Ignition Timing 18° BTDC, 0707-078" BTDC, 1.8mm-2.0mm (Full Advance)
C.D.l. Ignition - Specifications
Description Part Number
Resistance Test
Test Connections
Ignition Coil-Primary
tgnition Coil-Secondary
000-43-209-000
000-43-209-000
Spark Piug Cap 002-44-443-000
33 ohm + 15%
3900 ohms + 20% | Between High Tension
Charge Coil 000-43-205-000ASM | 150 ohms + 10%
Trigger Coll 000-43-205-000ASM | 2.2 ohms + 10%
Lighting Coil 000-43-205-000ASM | 18 ohms + 10%
5000 ohms = 10%
(+) Blue/White (— ) Black
Leads with caps removed
(+) Red/Black (—) Black/Red
(+) Black/White ( —) Black/Red
(+) Yellow ( —) Yellow
(+) Plug. Term. End ( —) Wire End
tgnition Timing
28° or .174 at 1800 RPM - 18° or .078 at 6000 RPM
64
———— rt me еее ee
Testing Point
Ignition Components
Before any disassembly of the ignition components is
started, a few simple test procedures should be car-
ried out to determine if the ignition system is truely the
problem. Many times, time and money are both
wasted in replacement of ignition components. when
the problem is elsewhere.
Below is a test procedure that has proven to cut time
in troubleshooting ignition problems. tt will first assist
you in pinpointing the problem area and then if elec-
trical, finding the problem.
ENGINE FAILS TO START
1-42 Remove the spark plug (plugs) from the engine
and inspect them to determine if they are fouled.
2-42 Place new spark plugs into the spark plug caps
and ground the spark plugs to the cylinder Be
sure the plugs are properly gapped.
3-42 Grasp the recoil hanale and crank the engine
over briskly. Observe the spark plug firing tip for
spark. Be sure the ignition switch is in the “ON
position.
4-42 1f no spark is seen, inspect the two black leads
to make sure they are in good condition. Inspect
the outer rubber coating of these wires, from the
engine to the ignition switch to make sure the in-
sulation isn't rubbed through anywhere, causing
a short circuit.
5-42 If the ignition switch leads are in good condition,
disconnect them from the ignition switch and
isolate the wire ends ta prevent them from
grounding. Grasp the recoil handle and once
again crank the engine over while observing the
spark plugs for spark. If spark is now present,
the ignition switch is faulty. If there isn't any
spark noted. the problem is with one of the igni-
tion components. Follow the procedure below,
using an onmmeter.
Ignition Coil
Resistance Test
(External)
PRIMARY WINDING
1-43 Disconnect both the ground lead (brown wire)
and the blue or blue/red lead from the ignition
coll
CUYUNA SERVICE MANUAL
2-43 Set the onmmeter scale selector knob to the X1
scale.
3-43 Touch the meter leads together and zero the
need'e.
4-43 Touch the ohmmeter leads to each of the spade
connectors of the ignition coil. If the primary win-
ding is in good condition the meter should read
1.9 ohms + 10%.
SECONDARY WINDING
1-44 Remove the spark plug cap from the spark plug
wire by rotating the cap counter-clockwise.
2-44 Disconnect both the blue and brown ground
leads from the ignition cot.
3-44 Set the ohmmeter selector knob on the X1K
scale.
4-44 Touch the ohmmeter leads together and zero the
meter needle.
5-44 Connect the red ohmmeter lead to the spark
wire. Touch the remaining black ohmmeter lead
to either of the spade connectors of the ignition
coil. The ohmmeter should read 5100 ohms +
15%.
CUYUNA SERVICE MANUAL
Ignition Generator
1-45 Remove the recoil starter Remove the starter
cup anc belt pulleys from the flywheel
2-45 Insert a small piece of cardboard between the
points to prevent them from making contact Do
this on both sets if you are working on a twin-
cylinder model.
3-46 Touch the red lead of the ohmmeter (set on X1)
to the center post of the condenser and ground
the black ohmmeter lead to the condenser case.
The ohmmeter must read open. !f the ohmmeter
shows continuity, the condenser must be replac-
ed.
4-46 Set the ohmmeter on X1K and repeat test. With
the meter set on X1K, you should note a slight
jump In the needle as the condenser takes on a
small charge from the ohmmeter. Reverse the
tester leads and you will again observe a slight
needie movement. This indicates the condenser
IS good.
3-45 Remove the blue lead from each ignition coi and
mare sure they are isolated from the engine.
Note their location so they can be re-installed
correctly. Also remove the two black leads from
the ignition switch and isolate them, make sure
they do not touch the air frame or engine.
4-45 Set the onmmeter selector knob on the X1 posi-
tion. Touch the tester leads together and zerc
the meter needle.
5-45 Touch the ohmmeter lead to each of the black ig-
nition leads. The ohm reading shouid be 3.7
ohms + 10%. -
Condenser Test
1-46 Disconnect the blue lead from each ignition coll
and isolate them so they do not touch the
engine.
2-46 Remove the recoil, starter cup and belt pulleys.
Using a couple of small cardboard pieces, block
both sets of points open.
Е NOTE: On the 215 single cylinder model, you
must block the points open and remove the
screw securing the remaining generating coil lead
to the stator plate. Make sure this ground lead
doesn’t touch any part of the engine during the
test procedure.
66
Spark Plug Cap
1-47 The Bosch spark plug cap is a 1000 ohm resistor
type cap. To test this component, first remove it
from the spark plug wire by turning it counter-
clockwise. Continue this rotation untit the cap is
free of the spark plug wire,
Sel the ohmmeter selector knob on X1K scale
and zero the needle.
Touch the two ohmmeter leads to either end of
the spark plug cap, making a good connection at
each end. The ohmmeter should register 1000
ohms + 10%,
Ignition Points
1-48 The ignition points can also be tested using the
ohmmeter to determine their condition. If the
points have been blocked open with cardboard
during previous test, remove the cardboard
allowing the points to make good contact. If the
points appear to be dirty pass the cardboard be-
tween the contacts severa! times to remove any
oil or any traces of dirt.
2.48 Set the ochmmeter selector knob on the X1 scale
and zero the needle.
3-48 Touch the two ohmmeter leads to either side of
the contact points. If more than 1 ohm resist
ance is registered, the points should be replac-
ed. Do not try tiling the point contacts to restore
them. Always install new points if the present set
doesn't meet the above specification or if they
are burnt or pitted.
Resistance Test
e CAUTION Y If the charging system is
being used to charge a battery, disconnect the
battery to prevent damage to the ohmmeter.
1-49 Disconnect the four charge coil wires from the
electrical system. These would be the two (2)
green and two (2) yellow wires. The two (2) green
wires are from the small 30 watt coll and the two
(2) yellow leads are from the 120 watt coll.
2-49 Set the ohmmeter scale selector on the X1 posi-
tion. Touch the tester leads together and zero
the meter.
3-49 Touch the red onmmeter lead to the areen wire
and the black ohmmeter lead to the green/black
wire Your tester should read 2.2 ohms + 10%.
4-49 Next, locate the solid yellow and yellow/black
wires. Touch the red tester lead to the solid
yellow wire and the black tester lead to the
vellowblack wire. The resistance should be 1.5
ohms + 10%.
CUYUNA SERVICE MANUAL
ignition Points
Replacement
+ 50 Remove lhe recoil starter cup, belt pulley and
flywheel from the engine. Refer to the engine
disassembly section of this manual for instruc-
tions covering removal of these components. To
aid in taking better photographs, the stator plate
has been removed from the engine However,
during ignition point replacement, it can be left in
place.
2-50 Using a small ignilion wrench, remove the nut
and lockwasher securing the blue and black
leads to the point set. Remove the wires.
=
3-50 Remove the single screw securing the point set
to the stator plate. Lift the point set free of the
stator plate.
4-50 Remove the new point set from its package and
account for the small tube of grease sent with
each set.
5-50 Apply the grease behind the point set rubbing
block as shown. Only a small amount Is required.
67
CUYUNA SERVICE MANUAL
6-50
Set the points into position on the stator plate
and secure with the single attaching screw. Be
sure the wires are routed properly under the
point plate before tightening the attaching
screw. If any of these wires are pinched. a short
circuit of the ignition system will result.
7-50 Position the blue and black wires onto the small
8-50
securing screw, next to the white nyion in-
sulating washer. Secure with nut and
lockwasher. Be sure that neither of the wire
brass eyelets touch any metal surfaces or the ig-
nition will be grounded. Hold the brass eyalels
wilh a needle nose pliers as the securing nut is
tightened lo prevent them from turning or
twisting.
After installing new points, pre-set the point gap
to .015. This can be done easiest by removing
the cam from the flywheel and installing it on the
crankshaft. Rotate the cam until its lobe comes
In contact with the point rubbing block. Continue
to rotate the cam until the points open tc their
widest gap. At this point, adjust the gap to 015.
Final point gap adjustment will be done during
engine timing.
Condenser
Replacement
1-51
2-51
3-51
4-51
Remove the recoil, starter cup, belt puiley
flywheel and fan housing from the engine. Refer
to the engine disassembly section of this
manual for instructions covering removal of
these components.
Scribe a reterence line on the stator plate and
fan housing for assembly purposes.
Remove the two screws that secure the stator
plate to the fan housing and remove the stator
plate,
Using a soldering gun, remove the black wires
from the top of the defective condenser.
En
.
5-51 From the backside of the stator plate, drive the
condenser tree of its mounting position.
5
Using a socket that is the same diameter as the
condenser, position socket, condenser and
stator plate between the jaws of a small vise.
Using the vise as a press, slowly close the vise
jaws, pressing the condenser into place.
7-51 Only press the condenser into the stator plate
until its tlat bottom surtace is flush with the bot-
tom edge of the mounting bore, Be careful not to
Kink or bulge the sices of the condenser case,
8-51 Using resin core solder, re-solder the two black
leads to the top of the new condenser Make
certain that these wires do not come in contact
with the condenser case or the ignition will be
shorted.
9-51 install the stator back into the fan nousing. meak-
Ing sure none of the wires are pinched on the
backside. Align the two scribe marks and secure
with the two screws and ¡:ockwashers. Engine
timing must be checked when engine IS re-
assembled
Procedure (P
1-52 Remove the reca:!, starter cup. belt pulieys and
spark plugs from the engine.
NOTE: Inspect the tiywheel to determine if
“E the advance arm spring has been removed. If
it hasn't, remove it using a needle nose pliers,
working through the opening in the flywheel face.
Grasp the spring at either end and carefully
stretch it out through the opening until it unhooks
from the advance arm and the stationary moun-
ting post and discard it. In using this method,
there is no need to remove the flywheel. Inspect
the spring once removed to be sure it hasn’
broken off, leaving part of the spring inside the
flywheel. The spring isn’t used with the new tim-
ing specification.
2-52 Locate the two screws securing the stator plate
to the fan housing Loosen these screws and
rotate the stator plate full clockwise (Tull retard-
ed) and re-tighten screws, securing the stator
plate in the full retardec position
EN NOTE: When adjusting the timing to the new
specifications (.070 - .078 or 1.8 - 2.0mm),
timing on both cylinders is set by adjusting the
point gap on each set of points. As pointed out
above, the advance spring must be removed to
assure easier starting. If the spring isn’t removed,
starting becomes very difficult.
CUYUNA SERVICE MANUAL
3-52 Install a dial indicator assembly into the spark
plug hole of the Number two (2) cylinder (fan
side).
4-52 Attach a continuity light or ohmmeter with one
lead to ground, the other lead io the biue/red coll
wire. Disco! mec: the wire from the coil.
5-52 Rotate the tiywheel clockwise and observe the
dial indicator needle movement. Continue ta
rotate the flywheel clockwise until the indicator
needie changes direction. Rotate the indicators
outer face until the zero on the dial, coincides
exactly at the point of direction change. Where
the indicator changes direction 1$ known as
(1.D.C) top dead center.
6-52 Hotate the flywheel counler-clockwise from
(T.D.C) top dead center, until the indicator nee-
dle indicates .070 to .078, or 1.8 to 2.0mm. At
this point, make sure the advance arm is pushed
fuily open or out against its stop.
CUYUNA SERVICE MANUAL
7-52 With the advance arm in the full advance posi
ton, the continuity light should dim in the range
of .070 to .078 or 1.8 to 2.0mm. If you are using
a ohmmeter, you should observe a needle
deflection if timing is correct. if neither of these
are observed, you must adjust the point gap to
correct timing.
Position the flywheel, so that the indicator nee-
dle indicates .078 or 2.0mm. While holding the
fywhee! in this position with one hand, insert a
screwdriver blade into the adjustment notch of
the point plate and between the two aluminum
post of the stator plate.
NOTE: There is no need to loosen the
screw securing the point set to the stator
plate. Leave it tight during this procedure and you
will save considerable time.
9-52 While holding the flywheei at .078 or 2.0 mm.
twist the screwdriver left or right while observ-
ing the continuity light or ohmmeter. As soon as
you note a light intensity change or needle
deflection, remove the screwdriver and recheck
timing. Rotate the flywheel counter-clockwise
until the needle indicates .100 (B.T.D CJ before
top dead center. Next rotate the flywheel
clockwise until you see the light change intensi-
ty, or the chmmeter needle deflect. S:op at that
exact point and note the indicator reading. It
must be between .070 10.078 0r 1.8 102.0 mm. If
the indicator needle is out of these specification,
again repeat all of step 8-52 89-52.
After you have the timing set on the #2 cylinder, install
the dial indicator into the #1 cylinder spark plug hole
(P.T.O. side) and repeat the same procedure. Both
cylinders must de timed within .002 or .05 mm of each
other.
11-52 When timing the number one cylinder, attach
the continuity tester lead to the solid blue wire.
It is found attached to the ignition coll nearest
the P.T.O, side or number one cylinder. Re-
install the blue/red wire on the number two igni-
tion coil.
70
ul NOTE: After the timing procedure is com-
pleted, rotate the {flywheel counter-
clockwise until the points are on the high side of
the cam or at their maximum open position,
observed through the largest opening in the
flywheel. Check gap using a feeler gauge. Point
gap must be between .012 to .016 or 0.71 to 0.81
mm.
Correct ignition timing will ignite the compressed
fuel/air mixture in the combustion chamber, just
before the piston reaches the top of its stroke. Timing
Is measured in distance from top dead center or in
degrees of crankshaft rotation.
Correct timing greatly influences performance. Im-
proper timing causes a decrease in horsepower,
overheating and increased fuel consumption, and can
also shorten engine life.
In the point ignition system, the breaker points on the
magneto stator plate work as a switch that interrupts
current flow from the generating coil to the primary
winding of the external ignition coil. if the point gap is
too small, current flow cannot be interrupted totally
because a small amount will jump the close gap. If the
gap Is too large, the quantity of current decreases
because the breaker points will interrupt the flow to
the primary, before the winding of the generating coil
are fully saturated. In either case, performance is in-
fluenced because high voltage cannot be produced
consistently.
Troubleshooting
CD Ignition
Tne troubleshooting procedure for the close circuit 1g-
nition system, is much different than what is used for
the standard open circuit type systems. In the stan-
dard open circuit ignitions, the ignition depends on an
open ignition switch to operate. In the “closed” cir-
cult ignition system, the ignition lead must be ground-
ed before the ignition will operate. To troubleshoot the
“closed ignition system. use the following pro-
cedure:
1-53 Remove the spark piugs and visually check elec-
trod condition. Replace any fouled plug. Attach
the spark plugs to the high tension leads and
ground them on the cylinder heads.
| NOTE: Make sure the ignition switch is in
the “ON” position, and both spark plugs are
grounded to the cylinder head.
2-53 Crank the engine over quickly and check for
spark. If no spark is seen, check to make sure
the ignition switch is “ON”, and that the there is
a good connection from the yellow/black ignition
wire to the switch and a good ground from the
switch to the engine. After making these checks,
again crank the engine over. If no spark is pre-
sent, proceed to step 3.
& CAUTION @ Spark plugs must be in-
stalled and grounded to engine. Never crank the
engine over without having the spark plugs at-
tached to the high tension leads and grounded, as
damage to the ё. D.I. unit may result.
3-53 Disconnect the yeliow/black !ead from the igni-
tion switch, then using a short piece of wire.
ground the yeilow/black wire to the engine (any
clean, unpainted metal surface) Crank the
engine over. If spark 's now present, the pro-
biem is either one or more of the following. A
Defective ignition switch. B. Corroded or ioose
wire connection at the ignition switch connec-
tor. C Poor ground connection.
To check these possible causes, proceed to
Switch Test”
'gnitio
Ignition Switch Test
Remove both the ground and ignition leads from
the ignition switch.
attach
the
Using an ohmmeter or continuity ight.
the two tester leads to either wire termina: o?
switch.
3-54 With the switch in the ciosed position. your
tester must show full continuity. the tester
shows an open circuit, double check your test
connections. If the connections are correct.
replace the switon.
nition
1-55 As stated before, this ignition system wili not
function unless it is first properly grounded. To
test for this, attach a short jumper lead to the
single yellow and black ignition wire. Ground the
jumper lead to any clean unpainted surface on
the engine,
2-55 With the spark plugs grounded ‘о the cylinder
heads, grasp the recoil rope anc crark the
engine over sharply. If spark is present at the
spark plug electrods, check the wiring harness
to and from the ignition switch for both a good
ground and tightness.
If no spark 15 present. proceed to checking the elec-
trical system components. using an onmmeter. When
testing the electrical system, always start by testing
the easier components tirst. When testing the dif-
ferent electrical components, there is one that cannot
be tested accurately. itis the C.D.{. box or amplifier. If
all the other components test ‘good’. the CD! unit
can then be assumed to be the problem. Al
resistance specifications and test connections are
given in an easy-to-follow test procedure.
71
CUYUNA SERVICE MANUAL
Spark Plug Cap
Res stance T est
1-56 Remove the spark plug caps from the high ten-
sion leads by turning them counter-clockwise.
2-56 Set the onmmeter selector on the X1K position,
then touch the leads together and zero the
meter.
3-56 In turn, on each cap. connect one meter lead to
one end of the cap, connect the other meter
lead to the other end of the cap.
4-56 Spark plug cap resistance must be 5000 ohms
+ 10%.
External Coil
(Primary Winding
Resistance)
1-57 Set the ohmmeter scale selector on the X1K
scale and zero the meter,
29-57 Test between the white/blue and black leads in
the double plug connector.
CUYUNA SERVICE MANUAL
3-57 The resistance must be 33 ohms + 15%
External Coil
(Secondary Winding
Resistance)
1-58 Set the ohmmeter scale selector on the X1K
position and zero the meter.
2-58 Remove the spark plug caps and perform the
test between the two high tension leads.
Argent
me rom À
3-58 The resistance must be 3900 ohms + 20%
Charge Coil
Resistance Test
1-59 Set the ohmmeter scale selector on the X100
scale.
2-59 Disconnect the triple and the double plug con-
nectors from the engine magneto to the CD!
unit. Test between the black/red lead in the triple
plug and the red/black lead in the double plug
connectors from the engine wiring harness
és a
3-59 The resistance must read 180 onms + 10%.
Resistance Test
1-60 Set the ohmmeter scale selector on the X1 posi-
tion and zero the meter.
2-60 Disconnect the triple and double plug connec-
tors from the C.D.I. unit. Perform test on wires
leading into the engine magneto.
3-60 Test between the black/white and blackired
leads in the triple piug.
4-60 The resistance must be 2.2 onms + 10%.
Lighting Coil
Resistance Test
1-61 Set the onmmeter scale selector on the X1 pasi-
tion and zero the meter.
2-61 Testbetween the two solid yellow leads found in
the double plug connector from the engine
magneto.
3-61 The resistance must be 18 ohms + 10%.
я u E
Checking Ignition
Timing
С.Э! ignition timing must be checked with the engine
running, using a good automotive timing light
The closed circuit C.D. ignition used on the Cuyuna
engine has a retarding timing curve. As the engine
RPM increases, you will note that timing actually
-etards instead of advancing as is so commonly seen.
With this type of retarding curve. the engine has Im-
oroved torque at lower engine speeds. To check
engine timing. follow the procedure below.
NOTE: With the C.D.l. ignition, each spark
ES plug fires twice per revolution and the igni-
tion advance mechanism is controlled electrical-
ly. Because both spark plugs fire at the same
time, it is only necessary to time one of the two
cylinders as the other will also be correct. Engine
timing must be checked at the specified RPM,
called out in the instructions.
1.62 Remove the spark plugs ‘rom the engine.
2-52 Install a dial indicator into the number two
cylinder (Magneto side). Locate top dead cenier
(T.D.C) and rotate the flywheel counter-
clockwise from top dead center 174 or 4.4mm
before top dead center (B.T.D.C.). While holding
the flywheel at .174 or 4.4mm, place a mark on
the flywheel that aligns with the long stationary
“run” indicator line of the fan housing.
3-62 Remove
the dial indicator and install spark
plugs. torauing them to 20 ft. ibs. Secure spark
plug wires to the spark plugs
44. WARNING 4&8 To avoid injury, stake air-
craft stationary while checking engine timing. Be
extremely careful around the propeller area.
4-62 Connect positive and negative ieads from timing
ight to power source and clamp the remaining
lead to either spark plug wire. Start engine and
run at 1800 RPM. Direct the timing light towards
the timing mark on the fan housing. At 1800
RPM, the scribed mark on the flywheel must
align with the stationary mark on the fan hous-
Ing.
5-62 If timing needs to be adjusted, remove the recol!
starter, starter cup and belt pulleys.
CUYUNA SERVICE MANUAL
6-62 Working through the openings provided in the
flywheel face, loosen the two stator plate fasten-
ing screws. Rotate the stator plate clockwise 10
retard the timing and counter-clockwise to ad-
vance liming. Re-tighten the two stator plate
screws and assemble starter assembly 10
engine. Bun the engine and re-check timing.
CUYUNA SERVICE MANUAL
CDI Diagnostic Test Sequence
Ignition Switches
Check for good
ground from yellow/
black to engine
Spark Plug
Cap Resistance
5000 ohm
Stator Plate
Resistance Test
— Exciter Coil |
— Pulser Coil }+—
CONDITION
1. Weak (yellow or no spark at spark plugs
2. Failure to arc 3/8" needle gap
3. Hard starting
4. Plug fouling
5. Mistire
6. Loss of power
INSPECT
Wire Harness
Connector Junction Blocks
Corroded Terminals
Stator to
CDI Box
CD! Box
to Sec. Coil
Secondary Coll
Test
Secondary Primary
Resistance Resistance
High Tension
Cable Leakage
74
CDI Control
Box
| Replace |
CUYUNA SERVICE MANUAL
Magneto Point Ignition
Diagnostic Test Sequence
CONDITION
Loss of power
1. Weak (yellow) or no spark plugs
2. Failure to arc 3/8" needle gap
3. Hard starting
4. Plug fouling
5. Misfire
6.
Ignition
Switches
INSPECT
Wire Harness
Terminal Connections
Connector Junction Blocks
Disconnect - Test
Spark Plug
Cap Res. Test
1000 ohm
Stator to
Secondary Coil
Stator Plate
Secondary Coil
Resistance Test
Breaker Points
Condition - Adjust
Engine Timing
Generator Coil
3.7 ohm
LC Condenser Test |
Test
] 1 |
Secondary Primary Coil Power
Resistance Resistance Test
High Tension
Cable Leakage
75
CUYUNA SERVICE MANUAL
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CUYUNA SERVICE MANUAL
Troubleshooting
Engine Performance.
shooting Section.
(ELECTRICAL)
TROUBLE PROBABLE CAUSE REMEDY
No lights. 1. Open Circuit: 1. Repair or replace faulty or damaged element.
Faulty Switch
Separated Connector
Cut Wiring.
2. Wiring shorted to ground: 2. Repair or replace damaged or faulty element.
Damaged Insulation.
= 3. Faulty Regulator 3. Replace regulator.
(Shorted SCH).
Dim lights. 1 Shorted lighting coil. 1 Replace armature piate or coil.
2. Faulty regulator - Incorrect | 2. Replace regulator.
regulator set point
(too low).
Burned out lights 1. Faulty regulator - Incorrect { 1. Replace regulator and failed bulbs.
(all). set point (too high).
Burned out lights 2. Failed bulb. 2. Replace bulb.
(individual).
Burned out lights. 3. Intermittent short in wire 3. Repair or replace wire harness
harness.
Engine won't run. 1 Open or shorted windings | 1. Replace armature plate.
in ignition coils (stator).
weak or no spark. 2 Open or shorted windings | 2. Replace external coti
in external ignition cor.
3. Shorted condanser - dirty | 3. Replace condenser.
or worn
-4. Damaged (burned) points. 14 Replace ports.
Engine won't run - 1. Burned or fouled plugs. 1, Replace plugs. Determine that correct plugs are
Adequate spark. being used. CHECK ENGINE TROUBLESHOOTING.
2. See Engine Trouble-
shooting Section.
Unacceptable 3. See Engine Trouble-
81
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