7
CARBURETOR
FLOODS
ENGINE
WILL NOT
ACCELERATE
ENGINE WILL
NOT IDLE
ENGINE RUNS
OUT LEAN
CARBURETOR
RUNS RICH
WITH HIGH
SPEED MIXTURE
SCREW SHUT
OFF
Dirt or foreign particles preventing
inlet needle from seating.
Diaphragm lever spring not seated
on lever dimple
Diaphragm improperly installed in
carburetor
Idle mixture too lean.
Incorrect setting on diaphragm lever.
Diaphragm cover plate loose.
Diaphragm gasket leaking
Main fuel orifice plugged
Incorrect idle adjustment
Idle discharge ports or channels
clogged.
Diaphragm lever set incorrectly.
Throttle shutter cocked in the throttle
bore causing fast idle.
Dirty nozzle check valve or outlet
screen.
Welch plug covering the idle discharge
ports does not seal. This causes the
engine to idle with idle mixture shut off.
Tank vent not operating correctly.
Leak in fuel system from tank to
pump
Ruptured fuel pump diaphragm
Main fuel orifice plugged
The 7/32 “ diameter nozzle welch
plug, or nozzle check valve cage, is
not sealing.
Remove, clean and replace
Remove lever and reinstall
Replace diaphragm or correct
installation.
Readjust
Reset
Tighten
Replace
Remove diaphragm cover,
diaphragm, diaphragm lever and
high speed mixture screw. Clean out
orifice by blowing through high
speed mixture screw threaded hole.
Reset to best idle
Blow out with compressed air, or, if
compressed air is not available,
clean and flush with gasoline.
Reset diaphragm lever so it is flush
with the floor of the diaphragm
chamber.
Reset
Clean or replace.
Replace welch plug, following
instructions outlined in service hints.
Clean, if possible, or replace
Tighten or replace fittings or line
Replace
Clean
Install new plug or
new cage
Note: IN MAKING CARBURETOR ADJUSTMENTS TURN ADJUSTMENTS
CAREFULLY AND GENTLY – DO NOT RAM ADJUSTMENTS INTO SEATS.
Set engine idling speed in accordance with engine manufacturer’s recommendation.
TROUBLE DATA
TROUBLE PROBLEM REMEDY
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