Kohler 24RCL Manual page 24

Problem/Condition Means of Identification
Gap-bridged spark Built-up deposits and gap between electrodes
plug closing.
Oil-fouled spark plug Wet, black deposits on the insulator shell, bore,
and electrodes.
Carbon-fouled spark Black, dry, fluffy carbon deposits on insulator
plug tips, exposed shell surfaces and electrodes.
Lead-fouled spark plug Dark gray, black, yellow, or tan deposits; or a
glazed coating on the insulator tip.
Pre-ignition damaged Melted electrodes and possibly blistered
spark plug insulator. Metallic deposits on insulator suggest
internal engine damage.
Overheated spark plug White or light gray insulator with small black or
gray/brown spots with bluish (burned)
appearance on electrodes.
Worn spark plug Severely eroded or worn electrodes.
Figure 2-6 Engine Evaluation Using Spark Plug Condition
13. Use a gapping tool to gently bend the side
electrode closer to or farther from the center
electrode to set the correct gap. See Figure 2-7.
Position the side electrode directly over the center
electrode.
Figure 2-7 Spark Plug Gap Adjustment
Note: Ensure that the spark plug tubes are seated
before installing the spark plugs. If the tubes
were removed, reinstall them before
installing the spark plugs.
24 Section 2 Scheduled Maintenance
Possible Cause/Solution
Oil or carbon fouling. Clean and regap the spark
plug.
Excessive oil entering combustion chamber
through worn rings and pistons, excessive
clearance between valve guides and stems, or
worn or loose bearings. Replace the spark plug.
Incorrect spark plug, weak ignition, clogged air
intake, overrich fuel mixture, or excessive
no-load operation. Clean and regap the spark
plug.
Caused by highly leaded fuel. Replace the spark
plug.
Wrong type of fuel, incorrect timing or advance,
too hot a plug, burned valves, or engine
overheating. Replace the spark plug.
Engine overheating, wrong type of fuel, loose
spark plugs, too hot a plug, low fuel pressure or
incorrect ignition timing. Replace the spark plug.
Caused by normal wear and failure to replace
spark plug at prescribed interval. Replace the
spark plug.
14. Reinstall the spark plug. Do not bump the electrode
against the cylinder head. Rotate the spark plug
clockwise until you feel resistance.
15. Use a torque wrench to tighten each spark plug to
the torque shown in Figure 2-8. Otherwise,
hand-tighten the spark plug until you feel
resistance.
Model
24RCL
30RCL and 38RCLB
Figure 2-8 Spark Plug Torque
16. Use a ratchet wrench to tighten an additional 1/4
turn. Do not overtighten, as doing so may strip the
threads or alter the electrode gap setting.
17. Check the spark plug wire connector in the boot for
1-511
accumulated dirt, grease, and other debris, and
clean as necessary.
18. Firmly push the spark plug boot onto the spark
plug.
19. Reconnect the generator set engine starting
battery, negative (--) lead last.
20. Reconnect the power for the battery charger.
Spark Plug Torque
18 Nm (13.3 ft. lbs.)
25 Nm (18.4 ft. lbs.)
TP-6907 5/16