FUEL SYSTEM / CARBURETION
4.15
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.
S
No fuel in tank
S
Restricted tank vent, or routed
improperly
S
Fuel lines or fuel valve restricted
S
Fuel filter plugged
S
Carburetor vent line(s) restricted
S
Plugged or restricted inlet needle
and seat screen or inlet passage
S
Clogged jets or passages
S
Float stuck, holding inlet needle
closed or inlet needle stuck
S
Float level too low
S
Fuel pump inoperative
S
Air leak at impulse line
S
Restricted impulse line (kinked,
pinched)
S
Intake air leak (throttle shaft, intake
ducts, airbox or air cleaner cover)
S
Ruptured vacuum slide diaphragm,
Vacuum slide stuck closed or sticky
S
Improper spring
S
Jet needle position incorrect
S
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.
S
Air intake restricted (inspect intake
duct)
S
Air filter dirty/plugged
S
Choke plunger sticking, incorrectly
adjusted choke
S
Choke cable binding or improperly
routed
S
Incorrect pilot air/fuel screw
adjustment
S
Faulty inlet needle and seat
S
Faulty inlet needle seat O-Ring
S
Float level too high
S
Poor fuel quality (old fuel)
S
Loose jets
S
Worn jet needle/needle jet or other
carburetor parts
S
Dirty carburetor (air bleed
passages or jets)
S
Weak or damaged vacuum piston
return spring
S
Fouled spark plug
POOR IDLE
Idle Too High
S
Idle adjusted improperly/idle
mixture screw damaged
S
Sticky vacuum slide
S
Throttle cable sticking, improperly
adjusted, routed incorrectly
S
Choke cable sticking, improperly
adjusted, routed incorrectly
S
Plugged or restricted idle jet
Idle Too Low
S
Choke cable bending or incorrectly
adjusted
S
Idle speed set incorrectly
S
Idle mixture screw misadjusted or
damaged
S
Belt dragging
S
Ignition timing incorrect
S
Worn jet needle/needle jet
S
Plugged or restricted idle jet
Erratic Idle
S
Choke cable bending or incorrectly
adjusted
S
Throttle cable incorrectly adjusted
S
Air leaks, dirty carburetor passages
(pilot circuit)
S
Pilot mixture screw damaged or
adjusted incorrectly
S
Tight valves
S
Ignition timing incorrect
S
Belt dragging
S
Dirty air cleaner
S
Engine worn
S
Spark plug fouled
S
Idle speed set incorrectly (speed
limiter)
S
Worn jet needle/needle jet
S
Plugged or restricted idle jet
Summary of Contents for 2005 Sportsman MV7
Page 58: ...MAINTENANCE 2 40 MAINTENANCE SCHEDULE Service Date Hours Miles Service Performed Serviced By...
Page 134: ...FUEL SYSTEM CARBURETION 4 16 NOTES...
Page 158: ...BODY STEERING SUSPENSION 5 24 NOTES...
Page 256: ...BRAKES 9 24 NOTES...
Page 302: ...ELECTRICAL 10 46 NOTES...
Page 303: ...ELECTRICAL WIRING DIAGRAM 2005 SPORTSMAN MV7 CIVILIAN VERSION...
Page 304: ...ELECTRICAL WIRING DIAGRAM 2005 SPORTSMAN MV7 CIVILIAN VERSION...