16
*NOTE: The actual low idle speed depends on the
application – refer to equipment
manufacturer’s recommendations. The
recommended low idle speed for basic
engines is 1200 RPM. To ensure best
results when setting the low idle fuel
needle, the low idle speed must not
exceed 1200 RPM (± 75 RPM).
5. Low Idle Fuel Needle Setting: Place the throttle
into the “idle” or “slow” position. Turn the low
idle fuel adjusting needle in (slowly) until engine
speed decreases and then back out approximately
3/4 to 1 turn to obtain the best low speed
performance.
6. Recheck the idle speed using a tachometer.
Readjust the speed as necessary.
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: 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.
Troubleshooting
If the MIL comes on, or the engine becomes hard to
start, runs roughly, or stalls at low idle speed, initial
checks should be made in the following areas:
•
Make sure the fuel tank is filled with clean,
fresh gasoline, and shut-off valve (if so
equipped)is opened completely.
•
Make sure fuel tank vent cap is not blocked and
it is operating properly.
•
Make sure the air cleaner element and
precleaner are clean and all components are
properly secured. Clean or replace as
necessary.
•
Make sure the proper fuel filter is being
used, and it is clean and unobstructed. Replace
filter only with genuine Kohler parts.
•
Make sure all connections to sensors, ECU,
and fuel injectors are properly secured.
•
Make sure a good 12 volt battery is being used
and is fully charged.
If these checks do not correct the problem, or the MIL
remains on, further diagnosis and servicing by an
authorized Kohler Engine Dealer is necessary.
Adjustment – EFI Throttle Body
Low Idle Speed (RPM) is the only adjustment that can
be made. All other fuel calibrations are controlled by
the ECU. The standard low idle speed is 1500 RPM*
(± 75 RPM).
*NOTE: The actual low idle speed depends on the
application -- refer to equipment
manufacturer's recommendations.
When an EFI engine is started cold, the ECU will
briefly set a higher (200-400 RPM) low idle speed,
similar to a fast idle. Do not attempt to perform any
readjustment during this "warm-up" period.
If adjustment is to be made, the engine must be at
operating temperature, air cleaner in place, and check
engine light must be off (no fault codes present).
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up.
2. Place the throttle control into the “idle” or “slow”
position.
3. Turn the low idle speed adjusting screw in or out
and check RPM with a tachometer. See Figure 19.
Figure 19. EFI Throttle Body Manifold.
Fuel Rail
Throttle Body
Intake Manifold
Low Idle Speed
Adjusting Screw
