2001 Polaris Sportsman 400-500 DUSE and H.O. Service Manual, Page 169Get this manual
FUEL SYSTEMCARBURETION
TROUBLESHOOTING
Fuel StarvationLean Mixture Symptoms: Hard start or no start, bog, backfire, popping through intakeexhaust, hesitation, detonation, low power, spark plug erosion, engine runs hot, surging, high idle, idle speed erratic& No fuel in tankRestricted tank vent, or routed improperlyFuel lines or fuel valve restrictedFuel filter pluggedCarburetor vent line(s) restrictedPlugged 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