1985-1995 Polaris ATV and Light Utility Hauler Service Manual, Page 370Get this manual
ENGINESCARBURETION Troubleshooting _Fuel StarvationLean Mixture Symptoms: Hard start or no start; Bogs, Backfires, Pops; Hesitation; Detonation; Low power; Spark plug erosion; Engine runs hot; Surging; Idles high, Idle varies No fuel in tank Restricted tank vent, or routed improperly Fuel lines or fuel valve restricted Fuel filter plugged Carburetor vent line(s) restricted Plugged or restricted inlet needle and seat screen or inlet passage Clogged jets or passages Float stuck, holding inlet needle closed or inlet needle stuck Float level too low Fuel pump inoperative Air leak at impulse line Restricted impulse line (kinked, pinched) Intake air leak (throttle shaft, intake ducts, airbox or air cleaner cover) Ruptured vacuum slide diaphragm; Vacuum slide stuck closed or sticky Improper spring Jet needle position incorrect Incorrect pilot screw adjustment Rich Mixture Symptoms: Fouls spark plugs; Black, sooty exhaust smoke; Rough idle; Poor fuel economy; Engine runs rough misses; Poor performance; Bogs; Engine loads up; Backfires, Pops Air intake restricted Air filter dirtyplugged Choke plunger sticking, incorrectly adjusted choke Choke cable binding or improperly routed Incorrect pilot screw adjustment Faulty inlet needle and seat Faulty inlet needle seat O-Ring Float level too high Poor fuel quality (old fuel) Loose jets Worn carburetor parts Dirty carburetor (air bleed passages or jets) Weak or damaged vacuum piston return spring Fouled Spark Plug Poor Idle Symptoms: Idles too high Idle adjusted improperlyidle mixture screw damaged Sticky vacuum slide Throttle cable sticking, improperly adjusted, routed incorrectly Choke cable sticking, improperly adjusted, routed incorrectly