1970-1979 Ski-Doo Snowmobiles Service Manual, Page 45Get this manual
CHAPTER THREE
TROUBLESHOOTING
Diagnosing snowmobile ills is relatively simple if you use orderly procedures and keep few basic principles in mindNever assume anythingDo not overlook the obviousIf you are riding along and the snowmobile suddenly quits, check the easiest, most accessible problem spots firstIs there gasoline in the tank? Has spark plug wire fallen off? Check the ignition switchMaybe that last mogul caused you to accidentally switch the emergency switch to OFF or pull the emergency stop "tether" stringIf nothing obvious turns up in cursory check, look little furtherLearning to recognize and describe symptoms will make repairs easier for you or mechanic at the shopDescribe problems accurately and fullySaying that "it won't run" isn't the same as saying "it quit at high speed and wouldn't start," or that "it sat in my garage for months and then wouldn't start Gather as many symptoms together as possible to aid in diagnosisNote whether the engine lost power gradually or all at once, what color smoke (if any) came from the exhaust, and so onRemember that the more complicated machine is, the easier it is to troubleshoot because symptoms point to specific problemsYou do not need fancy equipment or complicated test gear to determine whether repairs can