Kohler 4CKM Service Bulletin

2
SB-555 5/96
WARNING
Hazardous voltage. Moving rotor.
Can cause severe injury or death.
Operate generator set only with all guards and
electrical enclosures in place.
Grounding generator set. Hazardous voltage can
cause severe injury or death. Electrocution is possible
whenever electricity is present. Open main circuit
breakersofallpowersourcesbeforeservicingequipment.
Configure the installation to electrically ground the
generator set and electrical circuits when in use. Never
contact electrical leads or appliances when standing in
water or on wet ground, as the chance of electrocution is
increased under such conditions.
WARNING
Rotating parts.
Can cause severe injury or death.
Do not operate generator set without all guards,
screens, and covers in place.
Exposed moving parts can cause severe injury or
death. Keep hands, feet, hair, and clothing away from
belts and pulleys when unit is running. Replace guards,
covers, and screens before operating generator set.
The governor system consists of an electronic
isochronous governor, an electro-mechanical stepper
motor, and a magnetic pickup. Electrical pulses are
supplied by the magnetic pickup to the isochronous
governor(controlunit)eachtimeoneoftheringgearteeth
passes the pickup. The control unit compares the
frequency of these pulses to a preset reference and
provides a signal to the stepper motor which controls the
carburetorthrottlepositionandtheenginespeed.Thisisa
closed-loop system and typically provides steady-state
speed regulation of ± 0.25%.
Thefactorysets theelectronicgovernor andthegovernor
usuallyrequiresnofurtheradjustment.If the unitoperates
erratically, checkthefollowingitems beforereadjustment.
D Check the carburetor for dirt, grime, or
misadjustment. Also, check the idle-adjustment
screw. The screw should not prevent thethrottle
plate from completely closing. Also, check the
throttle linkage for any binding,dirt, damage, etc.
D Checkelectricalconnections—check thestepper
motor, controller box, and governor connector
(inside the controller) for clean and tight
connections.
D Checkelectricalgroundconnections—agoodDC
ground must be provided to the controller
assembly and governor circuit.
D Checkforagoodpositive12-voltDCsupply. Also
check if the positive voltagesupply is unstable or
below 8-volts DCmakingthecontrol unit function
erratically.
D Check magnetic pickup connections. Poor
connections may cause the signal to be erratic.
Aslongasthiserraticsignalisbeingsent, theunit
will not shut down due to loss of pickup.
D Checkfordirt builduponmagneticpickup—metal
filings or caked-on dirt/grease may decrease the
output signal of the magnetic pickup.
D Check for a loose coupling screw.
D Check for stepper motor/throttle shaft coupling
wear—if the roll pin wore the slot of the stepper
motor coupling, loosen couplingscrew andmove
coupling so that roll pin is positioned at a point in
stepper motor coupling without wear. Tighten
coupling screw.

Kohler 4CKM Specifications

General

Brand	Kohler
Model	4CKM
Category	Inverter
Language	English