12
Reduction Gear Units
On engines equipped with a reduction gear unit, remove
the oil plug on lower part of cover every 50 hours of
operation to check oil level. With the engine level, the oil
level of the unit should be up to the bottom of the oil plug
hole. To add oil, remove the vented plug at the top of the
unit. Use AGMA No. 7 EP oil in the reduction gear unit.
Following are a few products that meet this spec:
Mobilgear 634
Pennzoil Super Maxol ‘‘S’’
Pennzoil Maxol EP Gear Oil
Pennzoil Super Maxol EP Gear Oil
Pennzoil Super Pennztac EP Gear Oil
Carburetor Troubleshooting
and Adjustments
NOTE:
Carburetor adjustments should be made only
after the engine has warmed up.
These engines are equipped with one of two basic types
of fixed jet carburetors – Walbro or Nikki.
The carburetor is designed to deliver the correct
fuel-to-air mixture to the engine under all operating
conditions. On both types of carburetors, the fixed main
jet is calibrated at the factory and is not adjustable. On
Walbro carburetors, the low idle fuel adjusting needle is
set at the factory and normally does not need
adjustment. Certified engines may have a fixed idle or
limiter cap on the idle fuel adjusting needle. The idle fuel
can only be adjusted within the limits allowed by the
cap. Nikki carburetors have a sealed idle fuel adjusting
needle which is not adjustable.
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.
• 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:
Certified 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.
Walbro
Low Idle
Speed Adj.
Screw
Low Idle
Fuel Adj.
Needle
Nikki
Low Idle
Speed Adj.
Screw
Figure 13. Carburetors.
