Filter
Top Products
FUEL SYSTEM/CARBURETION
4.12
and check the surfaces for damage. Replace
diaphragms and gaskets as a set.
4. Reassemble the pump in the reverse order of
disassembly. Tighten all screws evenly.
TROUBLESHOOTING
FUEL STARVATION/L EAN 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)
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
Enfocus Software - Customer Support