2002 Polaris Universal Snowmobile Owners Manual - Page 115

MAINTENANCE General Maintenance A new engine can cause temporary spark plug fouling due to the preservative added during the assembly process. Avoid prolonged idle speeds, which cause plug fouling and carbonization. DUse recommended spark plugs with the proper gap. Refer to your Owner's Manual Supplement for specific information on your machine. DSpark plug torque is 18-22 ft. lbs. (2.5-3 kg/m). DAlways carry spare spark plugs in case of an emergency. The spark plug condition indicates how well the engine is operating. Check the color of the spark plug immediately after the engine has been warmed up and after the snowmobile has been driven at higher speeds. NOTE: Incorrect fuel mixture can often cause a spark plug to appear too dark or too light in color. Before changing spark plug heat ranges, be sure the correct main jet is installed in the carburetor(s). Refer to the Owner's Manual Supplement or see your dealer. Normal: The insulator tip is gray, tan, or light brown. There will be a few combustion deposits, but the electrodes are not burned or eroded. This indicates the spark plug is the proper type and heat range for the engine and the service. Overheating: The insulator tip is white. General causes are use of an improper spark plug or incorrect carburetion adjustments. Wet Fouled: The insulator tip is black. A damp, oily film covers the firing end, and there may be a carbon layer over the entire nose. Generally, the electrodes are not worn. General causes are excessive oil, use of non-recommended injection oil, excessive idling, idle set too low or too rich, or weak ignition output. 113