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CARBU.RETOR TRdUBLESHOOTlNG AND ADJUSTMENTS
Carburetor adjustments should be made on/y after engine has warmed up.
Kohler K91, K161 and K181 engines are equipped
with one of two basic types of carburetors - Kohler or
Walbro - fixed main jet or adjustable main jet.
The carburetor is designed to deliver the correct fuel-
to-air mixture to the engine under all operating
conditions. The main fuel and idle fuel needles on
adjustable jet carburetors are set at the factory and
normally do not require further adjustment. On fixed
jet carburetors, the low idle fuel needle is also set at
the factory and normally does not need further
adjustment. The main fuel jet is calibrated and
installed at the factory and is not adjustable*.
*NOTE: Engines operating at attitudes above
approximately 1830 m (6000 ft) may require
a special “high altitude” main jet.
TROUBLESHOOTING
If engine troubles are experienced that appear to be
caused by the carburetor, check the following areas
before adjusting 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 components as
necessary.
Make sure the air cleaner base and 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.
after checking the items listed above, starting or
engine operation problems exist, it may be
necessary to adjust or service the carburetor.
NOTE: Carburetor adjustments should be made
only after the engine has warmed up.
Kohler Carburetor Adjustment
1
.
With the engine stopped, turn the fuel adjusting
needles In (clockwise) until they bottom lightly.
NOTE: The tips of the fuel adjusting needles are
tapered to critical dimensions. Damage to
the needles and seats in carburetor body will
result if the needles are forced.
2 .
3 .
4.
Preliminary Settings: Turn the. adjusting
needles out (counterclockwise) from lightly
bottomed as follows:
1 KOHLER ADJ. 1 LOW IDLE
1 MAIN FUEL
I
K91 1 l-1/2 TURNS 1 2TURNS
I
K161 1 l-l/2 TURNS 1 3TURNS
K181
l-1/4 TURNS 2 TURNS
.
Start the engine and run at half-throttle for 5 to
IO minutes to warm-up. The engine must be
warm before making final settings (steps 4-6).
Main Fuel Needle Setting: This adjustment is
required for adjustable main jet carburetors
only. If the carburetor is a fixed main jet type
refer to Walbro adjustment.
Place the throttle into the Vast” position. If
possible, place the engine under load.
Turn the main fuel adjusting needle out
(counterclockwise) from the preliminary setting
until the 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.
10