11
Troubleshooting
If engine troubles are experienced that appear to be
fuel system related, 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.
• 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 element 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.
NOTE: Carburetor adjustments should be made only
after the engine has warmed up.
Kohler Carburetor Adjustment
1. With the engine stopped, turn the low idle fuel and
main fuel adjusting needles
in
(clockwise) until
they bottom
lightly
.
NOTE: The tip of the idle fuel and main fuel
adjusting needles are tapered to critical
dimensions. Damage to the needles and
the seats in carburetor body will result if
the needles are forced.
2.
Preliminary Settings:
Turn the adjusting needles
out
(counterclockwise) from lightly bottomed to
the positions shown in the chart below.
Battery Charging
WARNING: Explosive Gas!
Batteries produce explosive hydrogen gas while being
charged. To prevent a fire or explosion, charge
batteries only in well ventilated areas. Keep sparks,
open flames, and other sources of ignition away from
the battery at all times. Keep batteries out of the reach
of children. Remove all jewelry when servicing
batteries.
Before disconnecting the negative (–) ground cable,
make sure all switches are OFF. If ON, a spark will
occur at the ground cable terminal which could cause
an explosion if hydrogen gas or gasoline vapors are
present.
NOTE: Do not apply 12 volt DC to kill terminal of
ignition module as module will burn out.
Fuel Filter
Some engines are equipped with an in-line fuel filter.
Periodically inspect the filter and replace with a
genuine Kohler filter
every 200 operating hours
.
Carburetor Troubleshooting
and Adjustments
M18 and M20 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 altitudes above
approximately 1830 m (6000 ft.), may require
a special ‘‘high altitude’’ main jet. See your
Kohler Engine Service Dealer for further
information.
Kohler Adjustable Jet
Low Idle
Main Fuel
M18
1 turn
2-1/2 turns
M20
1 turn
2-1/2 turns
