Engine Tune-Up
determine the maximum no-load speed of the engine.
NOTE: Governor stops are used to limit the
compression of the governor spring, which
T h e n s t o p t h e e n g i n e a n d make the following
determines the maximum speed of the engine.
adjustments, if required:
1. Disconnect the booster spring and the stop lever
Adjust Idle Speed
spring.
2. Remove the variable speed spring housing and the
With the maximum no-load speed properly adjusted,
spring retainer from the governor housing.
adjust the idle speed as follows:
3. Refer to Table 1 and determine the stops or shims
1. Place the stop lever in the "run" position and the
required for the desired no-load speed.
speed control lever in the "idle" position.
2 . With the engine running at normal operating
4. Install the variable speed spring retainer and
temperature, back out the buffer screw to avoid contact
housing and tighten the two bolts.
with the differential lever.
5. Connect the booster spring and the stop lever
3 . Loosen the lock nut and turn the idle speed
spring. Start the engine and recheck the maximum no-
adjusting screw (Fig. 5) until the engine is operating
load speed.
at approximately 15 rpm below the recommended idle
speed.
6. If required, add or remove shims to obtain the
NOTE: The recommended idle speed is 550 rpm,
necessary operating speed. For each ,001" shim added,
but may vary with special engine applications.
t h e operating speed will increase approximately
1 rpm.
4. Hold the idle speed adjusting screw and tighten the
lock nut.
IMPORTANT: If the maximum no-load speed is
raised or lowered more than 50 rpm by the
installation or removal of shims, recheck the
Adjust Buffer Screw
governor gap. If readjustment of the governor
gap is required, the position of the injector
1. With the engine running at normal operating
racks must be rechecked.
temperatures, turn the buffer screw "in" (Fig. 6) so
Fig. 6 - Adjusting Buffer Screw
Fig. 7 - Adjusting Booster Spring
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