1970-1979 Ski-Doo Snowmobiles Service Manual, Page 50Get this manual
TROUBLESHOOTING Ignition Timing
Ignition timing that is too far advanced can cause "knocking" or "detonation Timing that is too retarded causes excessive heat buildup in the cylinder exhaust port areasSpark Plugs Spark plugs must be of correct heat rangeToo hot heat range can cause preignition and detonation which can ultimately result in piston burn-through as shown in Figure 8
malfunction are listed in logical sequence and in order of probabilityIgnition system malfunctions are outlined under Engine Starting and Engine Performance, covered earlierLights Will Not Light
abcdRefer to Chapter Two for recommended spark plugsPreignition
Bulbs are burned out Loose electrical connections Defective switch Defective lighting coil
Bulbs Burn Out Rapidly
Incorrect bulb type
Lights Too Bright or Too Dim