Polaris 2000 120 XCR, Service Manual

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4.34
ENGINE / CARBURETOR / CLUTCH
ENGINE MISFIRES
1. Incorrect or worn spark plug electrode gap. Adjust to
.025” (0.635 mm).
2. Ignition cable worn or cracked.
3. Spark weak.
4. Ignition wire connections loose.
5. Water in gasoline.
6. Insufficient compression.
ENGINE STOPS
1. Fuel tank empty. Water, dirt, gum, etc. in gasoline.
2. Vapor lock, i.e. gasoline evaporating in fuel lines due to
overheat around engine.
3. Vapor lock in fuel lines or carburetor due to use of too
volatile winter gas in warm season.
4. Air vent hole in fuel tank cap plugged.
5. Bearing parts seized due to lack of oil.
6. Magneto or ignition coil faulty.
ENGINE OVER HEATS
1. Crankcase oil level low. Add oil immediately.
2. Spark timing incorrect.
3. Low grade gasoline used, or engine is overloaded.
4. Cooling air circulation restricted.
5. Cooling air path misdirected causes loss of cooling
efficiency.
6. Cylinder head cooling fins clogged up with dirt.
7. Engine operated in an enclosed space without sufficient
cooling air.
8. Exhaust system restricted, or carbon deposits in
combustion chamber.
9. Engine running on low octane gasoline detonates due to
heavy load at low speed.
ENGINE KNOCKS
1. Poor quality gasoline.
2. Engine operating under heavy load at low speed.
3. Carbon deposits on cylinder head.
4. Spark timing incorrect.
5. Loose connecting rod bearing due to wear.
6. Loose piston pin due to wear.
ENGINE BACKFIRES THROUGH
CARBURETOR
1. Water or dirt in gasoline, or low grade gasoline.
2. Intake valve stuck.
3. Valves overheated, or hot carbon particles in combustion
chamber.
4. Engine cold.
= In. / mm.
Sparkplug Gap: .025" (.635mm)