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TROUBLESHOOTING
If engine troubles are experienced that appear to
be fuel system related, check the following areas
before adjusting or disassembling the carburetor.
•
Make sure the carburetor is. securely fastened
to the engine using gaskets in good condition.
•
Make sure the air cleaner element is clean
and all air cleaner components are fastened
securely.
•
Make sure the fuel tank is filled with clean,
fresh gasoline.
•
Make sure the fuel tank cap vent is not
blocked and that it is operating properly.
•
Make sure the ignition system, governor sys-
tem, exhaust system, and throttle and choke
controls are operating properly.
•
Make sure fuel is reaching the carburetor. This
includes checking the fuel shut-off valve, fuel
tank filter screen, in-line fuel filter, fuel lines,
and fuel pump for restrictions or faulty compo-
nents as necessary.
If, after checking the items listed above, starting
problems or other conditions similar to those listed
in the following table exist, it may be necessary to
adjust or service the carburetor.
Condition
Possible Cause/Probable Remedy
1.
Engine starts hard, or
1.
Idle fuel mixture or idle speed are improperly adjusted. Adjust the
runs roughly or stalls at
idle speed screw, then adjust idle fuel needle.
idle speed.
2.
Engine runs rich.
2a. Choke partially closed during operation. Check the choke lever and
(Indicated by black,
linkage to ensure choke is opening after warm-up.
sooty exhaust smoke,
b. Idle fuel mixture is improperly adjusted. Adjust idle fuel needle.
misfiring, loss of
c. Float level set too high. With fuel bowl removed and carburetor in-
speed and power,
governor hunting, or
verted, set exposed surface of float parallel with the bowl gasket
excessive throttle
surface of carburetor body.
opening.)
d. Dirt under fuel inlet needle. Remove needle. Clean needle and seat
and blow with compressed air.
e. Bowl vent or air bleeds plugged. Remove fuel bowl, idle fuel adjust-
ing needle, and welch plugs. Clean vent, ports, and air bleeds. Blow
out all passages with compressed air.
f. Fuel bowl gasket leaks. Remove fuel bowl and replace gasket.
g. Leaky, cracked, or damaged float. Submerge float to check for
leaks.
3.
Engine runs lean.
3a. Idle fuel mixture is improperly adjusted. Adjust idle fuel needle.
(Indicated by misfiring,
b. Float level set too low. With fuel bowl removed and carburetor in-
loss of speed and
verted, set exposed surface of float parallel with the bowl gasket
power, governor hunt-
surface of carburetor body.
ing, or excessive
c. Idle holes plugged; dirt in fuel delivery channels. Remove fuel bowl,
throttle opening.)
idle fuel adjusting needle, main fuel jet, and welch plugs. Clean all
passages and blow out with compressed air.
4.
Fuel leaks from
4a. Float level set too high. See Remedy 2c.
carburetor.
b. Dirt under fuel inlet needle. See Remedy 2d.
c. Bowl vent plugged. Remove fuel bowl and clean bowl vent. Blow out
with compressed air.
d. Float is cracked or damaged. Replace float.
e. Bowl retaining screw gasket damaged. Replace gasket.
f. Bowl retaining screw is not tightened. Torque screw to specifications.
6.12
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