Kohler LH690 Automobile Parts User Manual


 
16
Make sure the air cleaner element and precleaner
are clean and properly secured.
Make sure the air intake screen, blower housing,
and cooling surfaces of radiator are clean and free
of dirt and debris.
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.
Adjust Carburetor
Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm before
making final settings.
Low idle speed (RPM) setting:
1. Place the throttle control into the idle or slow
position. Set the low idle speed to 1200 RPM*
(± 75 RPM) by turning the low idle speed adjusting
screw (cable w/knob on some models) in or out.
Check the speed using a tachometer.
*NOTE: The actual low idle speed depends on the
application – refer to equipment
manufacturers recommendations. The
standard low idle speed is 1200 RPM.
2. If proper operation is not restored after adjusting
the low idle speed, carburetor servicing by an
authorized Kohler Engine Service Dealer may be
required.
Electronic Fuel Injection (EFI) System
The EFI system is a complete, electronically-controlled
fuel management system, designed to deliver a
precisely controlled fuel flow under all operating
conditions. The electronic control unit (ECU), the
‘‘brain’’ of the system, automatically adjusts fuel
delivery and ignition timing based upon load, speed,
operating temperature, and exhaust emission levels.
The low idle speed is the only manual adjustment
possible.
The ECU continuously monitors operation of the EFI
system. If it detects a problem or fault within the
system, it will illuminate the malfunction indicator
light (MIL), which is mounted in view of the operator.
This is a signal that normal, programmed operation
has been affected, and service by an authorized Kohler
Engine Dealer is required.
NOTE: The EFI system requires a rather complex
wiring harness to carry the electrical signals
between the sensors and the ECU. Do not
spray water at the wiring harness or any of
the electrical components, especially the ECU,
as it could cause malfunction, damage, or
failure.
Carburetor Troubleshooting and
Adjustments
In compliance with the government emission
standards, the carburetor is calibrated to deliver the
correct fuel-to-air mixture to the engine under all
operating conditions. The carburetor cannot be
adjusted, except for low idle speed (RPM). Carburetor
servicing is to be performed by an authorized Kohler
Engine Service Dealer only. See Figure 26.
NOTE: To ensure correct engine operating at
altitudes above 1525 meters (5000ft.), 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.
Idle Speed Adj.
Knob
Figure 26. Carburetor and Idle Speed Adjustment.
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. Replace the filter if it is dirty
or restricted.
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 cooling system is filled to the proper level.