Ski-Doo Formula S 1998, Shop Manual

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Section 03 TROUBLESHOOTING
Subsection 02 (ENGINE)
03-02-2
SYMPTOM ENGINE SUDDENLY TURNS OFF.
CONDITION NORMAL USE.
Test/Inspection 1. Perform engine leak test. Refer to engine leak verification flow chart. Check
possible piston seizure.
a. Damaged gasket and/or seal.
Replace defective parts.
2. “Four-corner” seizure of piston(s).
a. Accelerating too fast when engine is cold. Piston expands faster than cylinder.
Replace piston(s). Ask driver to refer to warm-up procedure in Operator’s Guide .
3. Piston(s) seizure on exhaust side (color on piston dome is correct).
a. Kinked fuel tank vent tube.
Relocate fuel tank vent tube.
b. Leaks at fuel line connections or damaged fuel lines.
Replace defective lines.
c. Fuel does not flow through carburetor(s) (plastic particles in needle area and/or
varnish formation in carburetor(s)).
Clean carburetor(s).
d. Spark plug heat range is too warm.
Install spark plug(s) with appropriate heat range (refer to TECHNICAL DATA 10).
e. Improper ignition timing.
Adjust according to specifications (refer to TECHNICAL DATA 10).
f. Restriction in exhaust system.
Replace.
g. Compression ratio is too high.
Install genuine parts.
h. Carburetor calibration is too lean.
Adjust according to specifications (refer to TECHNICAL DATA 10).
i. Improper rotary valve timing or improper valve.
Adjust according to specifications (refer to TECHNICAL DATA 10) and/or install
Bombardier’s recommended rotary valve.
j. Poor quality oil.
Use Bombardier Rotax oil.
k. Leaks at air intake silencer.
Replace air intake silencer grommets.