2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 138Get this manual

2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 138

CARBURATION AND FUEL SYSTEM TROUBLESHOOTING FUEL STARVATIONLEAN MIXTURE Symptoms: Hard start or no start, bog, backfire,
Incorrect pilot airfuel 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 jet needleneedle jet or other carburetor parts Dirty carburetor (air bleed passages
or jets) POOR IDLE Idle 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 Plugged or restricted
idle jet Idle Too Low Choke cable bending or incorrectly adjusted Idle speed set incorrectly Idle mixture screw misadjusted
or damaged Belt dragging Ignition timing incorrect Worn jet needleneedle jet Plugged or restricted idle jet Erratic Idle
Choke cable bending or incorrectly adjusted Throttle cable incorrectly adjusted Air leaks, dirty carburetor passages (pilot
circuit) Pilot mixture screw damaged or adjusted incorrectly Tight valves Ignition timing incorrect Belt dragging Dirty air