Engine Tune-Up
avoid contact with the differential lever, turn the idle
3. Stop the engine and, if necessary, adjust the no-load
speed as follows:
speed adjusting screw (Fig. 8) until the engine is
operating at approximately 15 rpm below the
a. Remove the high-speed spring retainer with tool J
recommended idle speed.
5895 and withdraw the high-speed spring and
plunger assembly.
NOTE: The recommended idle speed for non-
EPA certified engines is 500-600 rpm, but may
CAUTION: To prevent the low-speed spring and
vary with special engine applications.
cap from dropping into the governor, be careful
not to jar the assembly while it is being removed.
If the engine has a tendency to stall during deceleration,
install a new buffer screw. The current buffer screw
b. Remove the high-speed spring from the high-
uses a heavier spring and restricts the travel of the
speed spring plunger and add or remove shims as
differential lever to the off (no-fuel) position.
required to establish the desired engine no-load
speed.
2. Hold the idle screw and tighten the lock nut.
3. Install the high-speed spring retainer cover and
NOTE: For each .010"in shims added, the
tighten the two bolts.
engine speed will be increased approximately 10
rpm.
Adjust Buffer Screw
c.
Install the high-speed spring on the plunger and
With the idle speed properly set, adjust the buffer screw
install the spring assembly in the governor
as follows:
housing. Install the spring retainer in the governor
housing and tighten it securely. The maximum
1. With the engine running at normal operating
no-load speed varies with the full-load operating
temperature, turn the buffer screw in (Fig. 9) so it
speed desired.
contacts the differential lever as lightly as possible and
still eliminates engine roll.
d. Start the engine and recheck the no-load speed.
Repeat the procedure as necessary to establish
NOTE: Do not increase the engine idle speed
the no-load speed required.
more than 15 rpm with the buffer screw.
Adjust Idle Speed
2. Recheck the maximum no-load speed. If it has
increased more than 25 rpm, back off the buffer screw
With the maximum no-load speed properly adjusted,
until the increase is less than 25 rpm.
adjust the idle speed as follows:
3. Hold the buffer screw and tighten the lock nut.
1.
With the engine running at normal operating
temperature and with the buffer screw backed out to
Fig. 9 - Adjusting Buffer Screw
Fig. 8 - Adjusting Engine Idle Speed
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