SPARK PLUG
SPARK PLUG GAP / TORQUE
CAUTION
A hot exhaust system and engine can cause burns. Wear protective gloves
when removing a spark plug for inspection.
ELECTRODE GAP
NEW PLUG TORQUE
USED PLUG TORQUE
0.6 - 0.7 mm
9 - 11 ft. lbs.
(12 - 15 Nm)
17 - 20 ft. lbs.
(23 - 27 Nm)
NOTICE
Using non-recommended spark plugs can result in serious engine damage.
Use HAMMERHEAD-recommended spark plugs or their equivalent. See the
Specifications section for details.
Spark plug condition is indicative of engine operation. The spark plug firing end
condition should be read after the engine is warmed up and the vehicle is driven
at higher speeds. Immediately check the spark plug for correct color.
SPARK PLUG CONDITION
NORMAL SPARK PLUG
The normal insulator tip is gray, tan or light brown. There will be few combustion
deposits. The electrodes are not burned or eroded. This indicates the proper
type and heat range for the engine and the service.
TIP
The tip should not be white. A white insulator tip indicates overheating, caused
by use of an improper spark plug or incorrect throttle body adjustments.
WET FOULED SPARK PLUG
The wet fouled insulator tip is black. A damp oil film covers the firing end. There
may be a carbon layer over the entire nose. Generally, the electrodes are not
worn. General causes of fouling are excessive oil, use of non-recommended oil
or incorrect throttle body adjustments.
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