Polaris PRO XD Owner's Manual page 116

MAINTENANCE
CAUTION
A hot exhaust system and engine can cause burns. Wear protective gloves
when removing a spark plug for inspection.
To inspect the spark plugs, do the following:
1. Lift the cargo box to access the spark plugs.
2. Remove the spark plug cap. Using a ratchet and socket set, remove the plug
by rotating it counter-clockwise.
3. Reverse the procedure for spark plug installation.
4. Torque to specification.
NORMAL 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.
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 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 poor fuel quality.
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