Ski-Doo Formula 500 1998, Shop Manual

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Section 03 TROUBLESHOOTING
Subsection 02 (ENGINE)
03-02-5
SYMPTOM ENGINE DETONATION AT MAXIMUM RPM.
CONDITION NORMAL USE.
Test/Inspection 1. Check which type of fuel is used.
a. Octane number is too low and/or alcohol level is too high.
Use recommended fuel type.
2. Check spark plug type.
a. Improper spark plug heat range.
Install recommended spark plugs (refer to TECHNICAL DATA 10).
3. Check exhaust system.
a. Too much restriction.
Replace.
4. Check ignition timing.
a. Timing is too advanced.
Adjust according to specifications (refer to TECHNICAL DATA 10).
5. Check carburetion.
a. Fouled and/or improper carburetor components.
Clean or replace according to specifications (refer to TECHNICAL DATA 10).
6. Check compression ratio and combustion chamber volume.
a. Compression ratio is too high.
Install genuine parts.
SYMPTOM ENGINE TURNS OVER BUT FAILS TO START.
CONDITION NORMAL USE.
Test/Inspection 1. Check switches.
a. Ignition switch, emergency cut-out switch or tether switch is in the OFF position.
Place all switches in the RUN or ON position.
2. Check fuel level.
a. Mixture not rich enough to start cold engine.
Check fuel tank level and use primer.
3. Check spark plug.
a. Defective spark plug (no spark).
Replace spark plugs.
4. Check amount of fuel on spark plug.
a. Flooded engine (spark plug wet when removed).
Do not overprime or overchoke. Remove wet spark plugs, turn ignition switch to
OFF and crank engine several times. Install clean dry spark plugs. Start engine
following usual starting procedure.
5. Check fuel lines.
a. No fuel to the engine (spark plugs dry when removed).
Check fuel tank level; turn fuel valve on if applicable; check fuel filter, replace if
clogged; check condition of fuel and impulse lines and their connections.
6. Check engine compression.
a. Insufficient engine compression.
Replace defective part(s) (ex.: piston(s), ring(s), etc.).