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Fuel Filter
Some engines are equipped with an in-line fuel filter.
Periodically inspect the filter and replace when dirty.
Replacement is recommended annually or every 100
hours. Use a genuine Kohler filter.
Carburetor Troubleshooting and
Adjustments
NOTE: Carburetor adjustments should be made
only after the engine has warmed up.
These engines are equipped with a Walbro fixed main
jet carburetor. See Figure 13. Walbro carburetors have
a low idle speed adjustment screw, and either a fixed
or low idle fuel adjusting needle with a limiter cap.
Low Idle Fuel
Adjusting Needle
with Limiter
Figure 13. Carburetor.
The carburetor is designed to deliver the correct fuel-
to-air mixture to the engine under all operating
conditions. The main fuel jet is calibrated at the
factory and is not adjustable. The low idle fuel
adjusting needle is also set at the factory and
normally does not need adjustment.
NOTE: To ensure correct engine operation at
altitudes above 1525 meters (5000 ft.), it may
be necessary to have an authorized Kohler
dealer install a special high-altitude jet kit in
the carburetor. If a high-altitude kit has been
installed, the engine must be reconverted to
the original jet size, before it is operated at
lower altitudes, or overheating and engine
damage can result.
Troubleshooting
If engine troubles are experienced that appear to be
fuel system related, check the following areas before
adjusting the carburetor.
12
Low Idle Speed
Adjusting Screw
• 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.
• If the fuel tank is equipped with a shut-off valve,
make sure it is open.
• If the engine is equipped with an in-line fuel filter,
make sure it is clean and unobstructed. Replace
the filter if necessary.
• Make sure fuel is reaching the carburetor. This
includes checking the fuel lines and fuel pump for
restrictions or faulty components, replace as
necessary.
• Make sure the air cleaner element is clean and all
air cleaner components are fastened securely.
If, after checking the items listed above, the engine is
hard to start, runs roughly, or stalls at low idle speed,
it may be necessary to adjust or service the
carburetor.
Carburetor Adjustment
NOTE: These engines may have a fixed idle or limiter
cap on the idle fuel adjusting needle. Step 2
can only be performed within the limits
allowed by the cap.
1. Start the engine and run at half throttle for 5 to
10 minutes to warm up. The engine must be
warm before doing steps 2 and 3.
2. Low Idle Fuel Needle Setting: Place the throttle
into the "idle" or "slow" position.
Turn the low idle fuel adjusting needle out
(counterclockwise) from the preliminary setting
until engine speed decreases (rich). Note the
position of the needle.
Now turn the adjusting needle in (clockwise). The
engine speed may increase, then it will decrease
as the needle is turned in (lean). Note the position
of the needle.
Set the adjusting needle midway between the
rich and lean settings. See Figure 14.
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