5.24
Section 5
EFI Fuel System
If the governor/thro le components are all intact,
but you think there may be a problem with the
adjustment, follow Procedure A to check the se ing. If
the governor lever or the thro le body was loosened
or removed, go immediately to Procedure B to
perform the initial adjustment.
General
The idle speed is the only adjustment that may be
performed on the EFI system. The standard idle
speed se ing for EFI engines is 1500 RPM, but certain
applications might require a diff erent se ing. Check
the equipment manufacturer’s recommendation.
For starting and warm up, the ECU will adjust
the fuel and ignition timing, based upon ambient
temperature, engine temperature, and loads present.
In cold conditions, the idle speed will probably be
diff erent than normal for a few moments. Under other
conditions, the idle speed may actually start lower
than normal, but gradually increase to the established
se ing as operation continues. Do not a empt to
circumvent this warm up period, or readjust the
idle speed during this time. The engine must be
completely warmed up, in closed loop operating
mode for accurate idle adjustment.
Adjustment Procedure
1. Make sure there are no fault codes present in the
ECU memory.
2. Start the engine and allow it to fully warm up
and establish closed looped operation
(approximately 5-10 min.).
3. Place the thro le control in the idle/slow position
and check the idle speed with a tachometer. Turn
the idle speed screw in or out as required to
obtain 1500 RPM, or the idle speed specifi ed by
the equipment manufacturer. See Figure 5-23.
4. If the idle speed is adjusted up over 1800 RPM,
you must fi rst decrease idle RPM to 1500 RPM
and then up to fi nal idle speed se ing for the TPS
to be properly learned by the ECU.
5. The idle speed adjustment can aff ect the high idle
speed se ing. Move the thro le control to the full
thro le position and check the high idle speed.
Adjust as necessary to 3750 RPM, or the speed
specifi ed by the equipment manufacturer.
Initial Governor Adjustment
The initial governor adjustment is especially critical on
EFI engines because of the accuracy and sensitivity of
the electronic control system. Incorrect adjustment can
result in overspeed, loss of power, lack of response, or
inadequate load compensation. If you encounter any
of these symptoms and suspect them to be related to
the governor se ing, the following should be used to
check and/or adjust the governor and thro le linkage.
Figure 5-24. Throttle Linkage/Governor Lever
Connection.
A. Checking the Initial Adjustment
1. Unsnap the plastic linkage bushing a aching the
thro le linkage to the governor lever. See Figure
5-24. Unhook the damper spring from the lever,
separate the linkage from the bushing, and
remove the bushing from the lever. Mark the hole
position and unhook the governor spring from
the governor lever.
2. Pivot the thro le sha and plate assembly into
the Full Thro le position. Use a locking pliers
(needle nose works best) to temporarily clamp
the plate to the stop boss. Alternatively, there
may be a stop pin instead of the stop boss. See
Figure 5-25.
High-Speed
Throttle Stop
Pin
High-Speed
Throttle Stop
Boss
Figure 5-25. Throttle Details.
Linkage
Bushing
Throttle
Linkage
Damper
Spring
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