Engine Tune-Up
IMPORTANT: If the maximum no load speed is
raised or lowered more than 50 rpm by the
installation or removal of shims. recheck the
governor gap. If readjustment of the governor
gap is required, the position of the injector
racks must be rechecked.
NOTE: Governor stops are used to limit the
compression of the governor spring, which
determines the maximum speed of the engine.
Adjust Idle Speed
With the maximum no-load speed properly adjusted,
adjust the idle speed as follows:
Fig. 9 - Adjusting Booster Spring
1. Place the speed control lever in the idle position and
the stop lever in the run position.
Adjust Booster Spring
2 . With the engine running at normal operating
With the idle speed adjusted. adjust the booster spring
temperature, back out the buffer screw to avoid contact
as follows:
with the differential lever.
1. Move the speed control lever to the idle speed
3 . Loosen the lock nut and turn the idle speed
position.
adjusting screw (Fig. 7) until the engine is operating
at approximately 15 rpm below the recommended, idle
2. Refer to Fig. 9 and loosen the nut on the booster
speed.
spring retaining bolt on the governor speed control
lever. Loosen the lock nuts on the eye bolt at the
NOTE: The recommended idle speed is 550 rpm,
opposite end of the booster spring.
but may vary with special engine applications.
3. Move the bolt in the slot of the speed control lever
4. Hold the idle speed adjusting screw from turning
until the center of` the bolt is on or slightly over center
and tighten the lock nut.
(toward the idle speed position) of an imaginery line
through the bolt, lever shaft and eye bolt. Hold the
bolt from turning and tighten the lock nut.
Adjust Buffer Screw
4. Start the engine and move the speed control lever to
1. With the engine running at normal operating
the maximum speed position and release it. The speed
temperature, turn the buffer screw "in" (Fig. 8) so
control lever should return to the idle position. If it
that it contacts the differential lever as lightly as
does not. reduce the spring tension. If the lever does
possible and still eliminates engine roll.
return to the idle position, increase the tension of the
spring until the lever will not return to idle. Then
NOTE: Do not raise the idle speed more than 15
reduce the tension until the lever will return to idle
rpm with the buffer screw.
and tighten the lock nut on the eye bolt. This setting
2. Hold the buffer screw from turning and tighten the
will result in a minimum force required to operate the
lock nut.
speed control lever.
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