Kohler K91 Service Manual page 38

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 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 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.
Condition
1 .
Engine starts hard , or
runs roughly or stalls at
idle speed .
2 . E ngine runs rich .
(Indicated by black ,
sooty exhaust smoke ,
misfiring , loss of
speed and power ,
governor hunting , or
excessive throttle
opening . )
3 . Engine runs lea n .
(Indicated by misfiring ,
loss of speed and
power. governor hunt-
ing . or excessive
throttle opening . )
4 . Fuel leaks from
carburetor.
6. 1 2
Possible Cause/Probable Remedy
1 . Idle fuel mixture or idle speed are improperly adjusted. Adjust the
idle speed screw , then adjust idle fuel needle .
2a . Choke partially closed during operation . Check the choke lever and
linkage to ensure choke is opening after warm-up.
b . Idle fuel mixture is improperly adjusted. Adjust idle fuel needle .
c . Float level set too hig h . With fuel bowl removed and carburetor in-
verted , set exposed surface of float parallel with the bowl gasket
surface of carburetor body.
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 bleed s . 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 .
3a. Idle fuel mixture i s improperly adjusted . Adjust idle fuel needle .
b . Float level set too low . With fuel bowl removed and carburetor in-
verted , set exposed surface of float parallel with the bowl gasket
surface of carburetor body.
c . Idle holes plugged ; dirt in fuel delivery channels. Remove fuel bowl .
idle fuel adjusting needle. main fuel jet , and welch plugs. Clean all
passages and blow out with compressed air.
4a. Float level set too hig h . See Remedy 2c.
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.
•
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 ignition system , governor sys­
tem , exhaust syste m , and throttle and choke
controls are operating properly.
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.