Troubleshooting - Polaris SPORTSMAN 600 2003 Service Manual

FUEL SYSTEM/CARBURETION FUEL SYSTEM/CARBURETION

TROUBLESHOOTING

FUEL STARVATION/LEAN MIXTURE
Symptoms: Hard start or no start, bog, backfire,
popping through intake / exhaust, hesitation,
detonation, low power, spark plug erosion, engine
runs hot, surging, high idle, idle speed erratic.
G
No fuel in tank
G Restricted tank vent, or routed
improperly
G
Fuel lines or fuel valve restricted
G
Fuel filter plugged
G Carburetor vent line(s) restricted
G Plugged or restricted inlet needle
and seat screen or inlet passage
G Clogged jets or passages
G Float stuck, holding inlet needle
closed or inlet needle stuck
G Float level too low
G
Fuel pump inoperative
G Air leak at impulse line
G
Restricted impulse line (kinked,
pinched)
G
Intake air leak (throttle shaft, intake
ducts, airbox or air cleaner cover)
G
Ruptured vacuum slide diaphragm,
Vacuum slide stuck closed or sticky
G
Improper spring
G Jet needle position incorrect
G 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, bog, engine loads
up, backfire.
G
Air intake restricted (inspect intake
duct)
G Air filter dirty/plugged
G
Choke plunger sticking, incorrectly
adjusted choke
G
Choke cable binding or improperly
routed
G
Incorrect pilot air/fuel screw
adjustment
G
Faulty inlet needle and seat
G
Faulty inlet needle seat O-Ring
G Float level too high
G Poor fuel quality (old fuel)
4.12
G Loose jets
G Worn jet needle/needle jet or other
carburetor parts
G
Dirty carburetor (air bleed
passages or jets)
G Weak or damaged vacuum piston
return spring
G
Fouled spark plug
POOR IDLE
Idle Too High
G
Idle adjusted improperly/idle
mixture screw damaged
G Sticky vacuum slide
G Throttle cable sticking, improperly
adjusted, routed incorrectly
G Choke cable sticking, improperly
adjusted, routed incorrectly
G Plugged or restricted idle jet
Idle Too Low
G Choke cable bending or incorrectly
adjusted
G
Idle speed set incorrectly
G Idle mixture screw misadjusted or
damaged
G Belt dragging
G Ignition timing incorrect
G Worn jet needle/needle jet
G Plugged or restricted idle jet
Erratic Idle
G Choke cable bending or incorrectly
adjusted
G
Throttle cable incorrectly adjusted
G Air leaks, dirty carburetor passages
(pilot circuit)
G Pilot mixture screw damaged or
adjusted incorrectly
G Tight valves
G Ignition timing incorrect
G
Belt dragging
G
Dirty air cleaner
G Engine worn
G Spark plug fouled
G Idle speed set incorrectly (speed
limiter)
G Worn jet needle/needle jet
G
Plugged or restricted idle jet