Engine Tune-Up
11. Position the remaining injector rack control levers
as outlined in Steps 9 and 10.
is 500 rpm. However, the idle speed may vary with
special engine applications.
3. Hold the idle speed adjusting screw and tighten the
Adjust Maximum No-Load Speed
lock nut.
1. With the engine running, move the speed control
lever to the maximum speed position. Use an accurate
Adjust Buffer Screw
tachometer to determine the no-load speed of the
engine.
1. With the engine running at idle speed, turn the buffer
screw in (Fig. 7) so that it contacts the stop lever as
NOTE: Do not overspeed the engine.
lightly as possible and still eliminates engine roll.
2. Loosen the lock nut and adjust the maximum speed
NOTE: Do not raise the engine idle speed more
adjusting screw (Fig. 5) until the required no-load speed
than 20 rpm with the buffer screw. Check the
is obtained.
maximum no-load speed to make sure it has not
increased over 25 rpm by the buffer screw setting.
3. Hold the adjusting screw and tighten the lock nut.
Adjust Governor Booster Spring
Adjust Engine Idle Speed
The governor booster spring is used on some engines to
1. Make sure the stop lever is in the run position and
reduce the force necessary to move the speed control
place the speed control lever in the idle position.
lever from the idle speed position to the maximum
2.
With the engine running at normal operating
speed position. Adjust the booster spring as follows:
temperature, loosen the lock nut and turn the idle speed
1. Move the speed control lever to the idle speed
adjusting screw (Fig. 6) until the engine idles at the
position.
recommended speed. The recommended idle speed
2. Reduce the tension on the booster spring, if not
Fig. 6 - Adjusting Idle Speed
Fig. 5 - Adjusting Maximum No-Load Engine
Speed
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