2003 Ski-Doo REV Series Factory Shop Manual, Page 68Get this manual
Section 03 TROUBLESHOOTING Subsection 02 (ENGINE)
5Check thermostataThermostat reacts slowly or not at allReplace6Check antifreeze concentrationaAntifreeze concentration is too highAdjust concentration according to Bombardier's recommendations7Check tank capaCap does not hold pressureReplace8Check carburetionaImproperly adjusted or inadequate carburetor componentsAdjust according to specifications (refer to TECHNICAL DATA) or replace inadequate component(s)9Check cylinder head gasketsaWorn gasketsReplace10Check ignition timingaIgnition timing is too advancedAdjust according to specifications (refer to TECHNICAL DATA)11Check if there are leaks at air intake silencer andor engine crankcaseaLeak(s)Repair or replace12Check condition and heat range of spark plugsaMelted spark plug tip or inadequate heat rangeReplace