1999 Ski-Doo Factory Shop Manual Volume Three, Page 211Get this manual
Section 06 ELECTRICAL Subsection 03 (SPARK PLUGS)
DISASSEMBLY
First unscrew the spark plug turnClean the spark plug and cylinder head with pressurized air, then completely unscrew-
CAUTION
Severe engine damage might occur if wrong heat range plug is usedA too hot plug will result in overheating and preignition, etcA too cold plug will result in fouling (shorting the spark plug) or may create carbon build up which can heat up red-hot and cause pre-ignition or detonation
WARNING
Whenever using compressed air, always wear protective eye wear
HEAT RANGE