Kohler 4CKM Reference manual

SERVICEBULLETIN
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Original Issue Date: 5/96
Model: 4/5CKM/CKMR,4CFKM/CFKMR,7CCKM/CCKMR,7CCFKM/CCFKMR,
and 6.5RMY
Market: RV,Mobile,and Small Standby
Subject: KohlerElectronicGovernor(D-278670)Troubleshooting
KohlerGeneratorDivision,inanattempttoreducereturns
of functionalelectronicgovernors,created thisbulletinto
betterinform customers.Consult the ServiceManualfor
adjustmentproceduresnot found inthisbulletin.
ModelService Manual Publication Number
4/5CKM/CKMR
4CFKM/CFKMRTP-5394
7CCKM/CCKMR
7CCFKM/CCFKMRTP-5570
6.5RMYTP-5632
Figure 1.Service ManualSelection
OVER
SPEEDSPEEDGAIN
M3M4M2
70 M1
ADMP
MPNP2
P7
Figure 2.KohlerElectronicGovernorControl
Accidentalstarting.
Cancause severeinjuryordeath.
Disconnectbattery cablesbeforeworking on
generatorset(disconnectnegativelead firstand
reconnectitlast).
WARNING
Disabling generatorset.Accidentalstarting can
cause severeinjuryordeath.Disconnectbattery
cables(removenegativeleadfirstandreconnectitlast)to
disablegeneratorsetbeforeworking onthe generatorset
orconnected equipment. The generatorsetcan be
started bythe remotestart/stop switch unless this
precaution isfollowed.
Routing
Initial
Here
Service
ManagerSales ManagerParts ManagerTechnician No.1Technician No.2Technician No.3Return Thisto

2SB-555 5/96
WARNING
Hazardous voltage.Moving rotor.
Cancause severeinjuryordeath.
Operate generatorsetonlywith all guardsand
electricalenclosuresin place.
Grounding generatorset.Hazardous voltage can
cause severeinjuryordeath.Electrocution ispossible
wheneverelectricityispresent. Open maincircuit
breakersofallpowersourcesbeforeservicingequipment.
Configurethe installation to electricallyground the
generatorsetand electricalcircuitswhen in use.Never
contactelectrical leadsorapplianceswhen standing in
wateroron wetground,asthe chance ofelectrocution is
increased undersuchconditions.
WARNING
Rotating parts.
Cancause severeinjuryordeath.
Do notoperate generatorsetwithoutall guards,
screens,and coversin place.
Exposedmoving parts cancause severeinjuryor
death.Keep hands, feet, hair,and clothing awayfrom
beltsand pulleys when unitisrunning.Replace guards,
covers,and screensbefore operating generatorset.
The governorsystemconsistsofan electronic
isochronousgovernor,an electro-mechanicalstepper
motor,and a magneticpickup.Electricalpulsesare
supplied bythe magneticpickup tothe isochronous
governor(controlunit)eachtimeoneoftheringgearteeth
passesthe pickup.The controlunitcomparesthe
frequency of these pulsesto a presetreference and
providesasignaltothe stepper motorwhichcontrolsthe
carburetorthrottlepositionandtheenginespeed.Thisisa
closed-loop systemand typicallyprovides steady-state
speed regulation of±0.25%.
Thefactory setstheelectronicgovernorandthegovernor
usuallyrequiresnofurtheradjustment.Iftheunitoperates
erratically,check thefollowingitemsbeforereadjustment.
DCheck the carburetorfordirt, grime,or
misadjustment. Also,check the idle-adjustment
screw.The screwshould notprevent the throttle
platefromcompletely closing.Also,check the
throttlelinkage foranybinding,dirt, damage,etc.
DCheck electricalconnections—check thestepper
motor,controllerbox,and governorconnector
(inside the controller) forclean and tight
connections.
DCheckelectricalgroundconnections—agoodDC
ground mustbe provided tothe controller
assemblyand governorcircuit.
DCheckforagoodpositive12-voltDCsupply.Also
check if the positivevoltage supplyisunstable or
below8-voltsDCmaking thecontrolunit function
erratically.
DCheck magneticpickup connections.Poor
connectionsmay causethe signalto be erratic.
Aslongasthiserraticsignalisbeingsent, theunit
will notshutdown due toloss ofpickup.
DCheck fordirtbuilduponmagneticpickup—metal
filingsorcaked-on dirt/greasemaydecreasethe
outputsignalof the magneticpickup.
DCheck foraloosecoupling screw.
DCheck forstepper motor/throttleshaft coupling
wear—if the roll pinworethe slotof the stepper
motorcoupling,loosen coupling screwandmove
coupling sothatroll pinispositioned ata pointin
stepper motorcoupling withoutwear.Tighten
coupling screw.

3
SB-555 5/96
MagneticPickup
(See Figure3orFigure 4)
The magneticpickup providesan ACsignaltothe control
unit. Minimumvoltage output fromthe pickup during
engine cranking should be 1.75 VAC.
AirGap
(See Figure3orFigure 4)
The airgap between the ring gearand pickup should be
0.040 inches.
NOTE
Measurethe airgap at3 or4 placesto getan accurate
reading.
To adjustairgap,loosen the locknutand turn pickup
clockwise until itjustbottomson the ring gear, then back
out3/4turns.
Hold pickup inthisposition whileretightening locknut.
If loss ofsignalorfailure of the pickup occurswhile
running, the governorcontrol will de-energizethe
carburetorshut-off solenoidtostop the engine.
2
1
4
3
TP-5572-6
1.0.04-in.airgap
2.Top of flywheelring geartooth
3.Magneticpickup generatesan ACvoltage
4.Locknut
Figure 3.MagneticPickup AirGap
(4/5CKM/CKMRand 6.5RMY)
12
TP-5572-6
1. Ignition coil
2.Magneticpickup
Figure 4.MagneticPickup (7CCKM/CCKMR)

4SB-555 5/96
Actuator
(See Figure5and Figure 6)
The actuatorconsistsofastepper motorcoupled tothe
carburetorthrottleshaft.
It receives signalsfromthe governorcontrolunitand
rotatesthe shaft tothe properposition.
Totest forproperoperation of the actuator,disconnect
magneticpickup leads.Manuallymovethe throttle
shaft/governorstepper motorfully counterclockwise
(closed throttle).Startgeneratorset. Actuatorshould
initiallymoveclockwise(wide-open throttle)and thenturn
completely counterclockwise.The actuatorshould
remaininthisposition.Stopgeneratorset. If actuatorfails
thistest, replace actuator.
The governoractuatorshouldfunction withsteadyand
smoothmovementduring operation. If movementof
actuatoriserraticorlarge changesinmovementoccur:
DCheck shaft alignment—ensurethat the actuator
and throttleshaftsareconcentricand that the
throttle-shaft pinisatmidpointoftheactuatorslot
DCheck forexcessivecoupling slotwear—replace
worn parts
DCheck forbroken orloosewiring including plug
connections
Adjustcoupling sothrottleshaft pinisrecessed tothe
middle of the slot.
Stepper-motor rotationalposition adjustmentisnot
necessary.Throttle plate position can be eitheropen or
closed during assembly.
Onlytwo actuatorleadsofeachcoil group are utilized.
(BLK-YEL,and RED-WHT.)Resistance perphase:38.5
ohms.
Voltage pulsesreceived fromthe governorcontrol
determine movementof the stepper motor.
NOTE
A12-VDCvoltageappliedtothemotorleadswillresultina
single-step movementof1.8_.Reversalof the voltage
polaritywill resultin a 1.8_movementinthe reverse
direction.
NOTE
Thesteppermotorwillnotcontinuouslyrotatewithbattery
voltage supplied toitswindings.
TOP VIEW
12
3
4
5
6
7
4
1
TP-5572-6
1.Actuator
2.Coupling
3.Closed throttle
4. Intake airflow
5.Pin
6.Setscrew
7. Open throttle
Figure 5.Actuator(StepperMotor)
YEL
BLK
GRN
REDWHTBLUTP-5572-6
Figure 6.ActuatorCoil Group

5
SB-555 5/96
GovernorControl
The electronic controlboard providespowertothe
actuator. It alsocontrolsenergizing and de-energizing of
the fuel—anti-diesel(AD)solenoid orgas valve.
Priorto anygovernoradjustments:
1. Open the line circuitbreakerbetween the generator
and anyloadswhichmaybe frequency sensitive.
2.Connectafrequency metertothe generatorAC
outputin ordertomonitorACoutputwhilemaking
adjustments.
SpeedAdjustment
Turnspeed potentiometerclockwisetoincreasespeed,
counterclockwiseto decreasespeed.See Figure 7.
SPEEDGAIN
OVER
SPEED
60 Hz=1800 RPM
50 Hz=1500 RPM
4-PoleGenerators
TP-5572-6
Figure 7.SpeedPotentiometer
GainAdjustment
The GainPotentiometer (Pot)pertainsto governor
sensitivity.See Figure 8.
GAIN
TP-5572-6
Figure 8. GainPotentiometer
DMoveGainPotin1/8-turnincrementsifhuntingor
surging occurs.
DChanging the GainPotsetting mayaffect the
governorSpeed Pot.
DGovernorSpeed Potadjustmentwill notaffect
the GainPot.

6SB-555 5/96
OverspeedAdjustment
The governorcontrolcontainsacircuitwhichwill
de-energizethe carburetorfuelsolenoid(AD)if the
generatorexceedsthe overspeed setting.
SPEED
TP-5572-6
Figure 9.SpeedPotentiometer
DDonotusetheSpeedPottocheck theoverspeed
shutdownsetpoint. See Figure 9.
DDisconnectall loadsfromthe generatorwhen
adjusting the overspeed cutout.
1.Connectafrequency metertothe generatoroutput.
2.TurnOverspeed Potcounterclockwisetomax.
overspeed cut-outpoint. See Figure 10.
OVERSPEED
TP-5572-6
Figure 10. OverspeedPotentiometer
3.While observing the frequency meter,manuallyturn
the governoractuatorshaft until frequency reaches
the desired cut-outspeed.
NOTE
Do notexceed 72 Hertz
4.Whilekeeping the generatorat the desired cut-in
speed,slowlyturnOverspeedPotclockwiseuntilunit
shutsdown.See Figure 11.
OVERSPEED
TP-5572-6
Figure 11. OverspeedPotentiometer
NOTE
If OverspeedPotisadjustedtoolow, theenginemay shut
downonstartup because ofgovernorovershoot.

7
SB-555 5/96
Condition (Fault) Result
Loss ofpickup whilerunning Throttlemovestoclosed position and fuelshut-off solenoid de-energizes
(gensetshutdown)
Engine overspeed Fuelshut-off solenoid de-energizes(gensetshutdown)
Breakof fuelshut-off solenoidlead Fuelshut-off solenoid de-energizes
Loss ofDC powerto governorassemblyFuelshut-off solenoid de-energizes(gensetshutdown)
Breakofstepper motorleadsErraticperformancethen fuelshut-off solenoid de-energizes(gensetshutdown)
Actuatorlinkage failureErraticperformancethen fuelshut-off solenoid de-energizes(gensetshutdown)
Figure 12.ElectronicGovernorFaultShutdownConditions and Results
1
2
3
4
5
6
1
2
3
4
5
6
16
17
9
10
16
17
9
10
1
2
3
4
1
2
3
4
P9 J9 P4 J4 P7 J7
WHT.
YEL.
BLK.
RED
GRN.
BLU.
M2
M4
M3
M1
M2
M4
M3
M1
GOVERNOR
ACTUATOR
10
N10
11 11
7 7
11
13
11
13
MP
MP
MAGNETIC
PICKUP
CARB.
1 1 9 9
6 6
ADAD
AD
MP
MP
70
70
B+
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
17 18 19 20
1234
8 7 6 5
12 11 10 9
16 15 14 13
20 19 18 17
1 2
3 4
5 6
2 1
4 3
6 5
123
6 5 4
9 8 7
12 11 10
TP-5572-6
Figure 13.ElectronicGovernorSchematic(Typical)
SchematicLine
GOVERNORMP
MP
MPSTM
BLACK
YEL
GREEN
P6--5SPEEDGAINOVER
SPEED
ELECTRONIC
GOVERNORBOARD
MAGNETIC
PICKUP
SENSOR
YELLOW
WHITE
BLACK
GREEN
RED
BLUESTEPPER
MOTOR
P6--6TP-5572-6
Figure 14.SchematicSymbols(Typical)