1997 Ski-Doo Factory Shop Manual Volume One, Page 48Get this manual
Section 02 TROUBLESHOOTING Sub-Section 05 (ELECTRICAL SYSTEM)
SYMPTOM CONDITION TestInspection
FOULED (BLACK) SPARK PLUG TIPNORMAL USE1Check carburetor(s)aCarburetion is too richAdjust according to specifications (refer to TECHNCAL DATA 09)2Check injection oil consumptionaInjection pump flow is too highAdjust according to specification or replace3Check oil qualityaPoor oil quality that creates depositsUse Bombardier oil4Check engine compressionaLeaking piston ring(s)Replace
SYMPTOM CONDITION TestInspection