1999 Ski-Doo Factory Shop Manual Volume Two, Page 59Get this manual
Section 03 TROUBLESHOOTING Subsection 02 (ENGINE)
SYMPTOM CONDITION TestInspection
ENGINE DETONATION AT MAXIMUM RPMNORMAL USE1Check which type of fuel is usedaOctane number is too low andor alcohol level is too highUse recommended fuel type2Check spark plug typeaImproper spark plug heat rangeInstall recommended spark plugs (refer to TECHNICAL DATA 10)3Check exhaust systemaToo much restrictionReplace4Check ignition timingaTiming is too advancedAdjust according to specifications (refer to TECHNICAL DATA 10)5Check carburetionaFouled andor improper carburetor componentsClean or replace according to specifications (refer to TECHNICAL DATA 10)6Check compression ratio and combustion chamber volumeaCompression ratio is too highInstall genuine parts