Polaris Virage TX 2000 Service Manual page 58

MAINTENANCE/TUNE UP
Troubleshooting
Rich Fuel Mixture
Symptoms: Fouled sparkplugs; black sooty exhaust; rough idle, idle unstable; poor fuel economy; rough running
("four cycling"); misses; poor performance; bogs; loads up; backfires (plug fouling).
• Thermostat/popoff leak, dirty or damaged
• Carburetor mixture needles damaged or adjusted incorrectly
• Needle and seat damaged
• Misuse of choke
• Fouled spark plugs
• Fuel pump diaphragm damaged (ruptured)
• Carburetor synchronization incorrect
• Needle and seat control arm too high or sticking
• Collapsed exhaust hose or pipe (restricted)
• Air intake restricted
• Broken, cracked or poorly sealing reed valve
• Low compression
• Ignition problem
• Anti-siphon valve worn or broken
Symptoms: Engine backfires.
• Weak spark from fouled, defective, worn or wrong spark plugs
• Broken reed petals
Symptoms: Engine "pinging" or "knocking".
• Lean fuel mixture
• Poor quality, low octane gasoline
• Incorrect ignition timing
• Spark plug heat range too high
Symptoms: Engine power loss.
• Weak spark
• Incorrect fuel or fuel mixture
• Water in fuel system or oil tank
• Fuel filter restricted
• Jet intake clogged
• Cooling system clogged
Symptoms: Engine noise.
• Detonation (see causes for holed or eroded pistons, this section)
• Excessive piston clearance
• Exhaust leak, loose exhaust pipe or muffler (water box)
• Engine mounts or mount plate loose or rubber mounts broken
• Drive coupler splines dry
• Driveshaft runout excessive
• Driveshaft end play incorrect; rubber dampers worn or missing
• Broken ring or ring land
• Oil pump bushing end play excessive
• Ignition timing incorrect
• Piston pin damaged or bent
• Connecting rod bearing failure (small end or big end)
• Crankshaft main bearing failure or wear
• Flywheel loose
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