2004 Bombardier Quest/Traxter Series Shop Manual, Page 74Get this manual
Section 03 ENGINE QUEST Subsection 02 (TROUBLESHOOTING)
ENGINE GENERAL
SYMPTOM CONDITION TestInspection ENGINE BACKFIRESNORMAL USE1Check spark plug andor electrical systemaCarbon accumulation caused by defective spark plugClean carbon accumulation and replace spark plugbElectrical system has failureReplace defective part(s)2Check leakage on intake manifoldair filter boxaAir leak on intake systemRetighten screws andor replace intake manifoldair filter box3Check exhaust air leakingaExhaust gasket is leakingRetighten screws andor replace exhaust gasket4Check intake valve(s) for leakingaIntake valve(s) is (are) leakingRepair or replace valve(s)5Check if fuel supply is insufficient at high RPMaFuel line is contaminated andor bent (engine gets lean)Clean andor replace defective part(s)6Check calibration of carburatoraWrong carburator adjustment (engine to lean)Clean and readjust carburatorSYMPTOM CONDITION TestInspection ENGINE SUDDENLY TURNS OFFNORMAL USE1Check spark plug cap contact andor cableaSpark plug cap looseReplug capbSpark plug cable melted andor damagedReplace spark plug cable2Check condition of spark plug (blue spark ideal)aRed, jumping spark means damaged spark plugReplace spark plug with appropriate heat range (refer to TECHNICAL DATA)bCondition of spark plugReadjust carburator andor replace spark plug