Kohler 4EFRKM, Operation, Page: 23 / 40

TP-6081 4/00 11 Section 3 Scheduled Maintenance
3.7 Cooling Areas
Cleaning the Air Intake/Cooling Areas
To prevent generator shutdown or damage because of
overheating, keep the cooling air inlets clean and
unobstructed at all times. At the intervals specified in the
service schedule, check and/or clean the cooling areas.
Cleaning Procedure
1. Remove the blower housing and other cooling
shrouds.
2. Clean the cooling fins and external surfaces as
necessary.
3. Reinstall the cooling shrouds and blower housing.
3.8 Ignition System
Service the spark plug at the interval specified in the
service schedule using the following procedure.
Spark Plug Service Procedure
1. Remove the spark plug wire by grasping the spark
plug boot and turning it slightly while pulling. Do not
pull the wire. Pulling on the wire rather than the
boot may damage the wire or the terminal.
2. Use compressed air to remove dirt from around the
spark plug to prevent dirt particles from falling into
the combustion chamber.
3. Loosen the spark plug with a ratchet and 5/8 in.
spark plug socket with a rubber insert to prevent
spark plug damage.
4. Remove the spark plug and examine it. A spark
plug in good operating condition will have a light tan
or gray deposit on the firing tip. See Figure 3-4 to
evaluate the engine condition by color/condition of
a problem spark plug.
Problem/Condition Means of Identification Possible Cause
Gap-bridged spark plug Built-up deposits and gap between the
electrodes closing Oil or carbon fouling. Clean and regap
the spark plug.
Oil-fouled spark plug Wet, black deposits on the insulator
shell, bore, and electrode Excessive oil entering the combustion
chamber through the worn rings and
pistons, excessive clearance between
valve guides and stems, or worn or
loose bearings. Replace the spark plug.
Carbon-fouled spark plug Black, dry, fluffy carbon deposits on the
insulator tips, exposed shell surfaces,
and electrodes Incorrect spark plug, weak ignition,
clogged air intake, defective fuel pump,
overrich fuel mixture, or excessive
no-load operation. Clean and regap the
spark plug.
Lead-fouled spark plug Dark gray, black, yellow, or tan deposits;
a glazed coating on the insulator tip Caused by highly leaded fuel. Replace
the spark plug.
Preignition-damaged spark plug Melted electrodes and possibly blistered
insulator. Metallic deposits on the
insulator suggest internal engine
damage Wrong type of fuel, incorrect timing or
advance, too hot a plug, burned valves,
or engine overheating. Replace the
spark plug.
Overheated spark plug White or light gray insulator with small
black or gray/brown spots with bluish
(burned) appearance on the electrodes Engine overheating, wrong type of fuel,
loose spark plug, too hot a plug, low fuel
pump pressure, or incorrect ignition
timing. Replace the spark plug.
Worn spark plug Severely eroded or worn electrodes Caused by normal wear and failure to
replace spark plug at prescribed
interval. Replace the spark plug.
Figure 3-4 Engine Evaluation Using Spark Plug Condition