DETROIT DIESEL
Engine Tune-Up
1. Place the stop lever in the run position and the
speed control lever in the idle position.
Fig. 8 - Adjusting Buffer Screw
Fig. 7 Adjusting Idle Speed
2. With the engine running at normal operating
temperature, back out the buffer screw to avoid contact
with the differential lever.
3. Loosen the lock nut and turn the idle speed
adjusting screw (Fig. 7) until the engine is operating at
approximately 15 rpm below the recommended idle
speed. The recommended idle speed is 550 rpm, but
may vary with special engine applications.
4. Hold the idle speed adjusting screw and tighten the
lock nut.
*Maximum amount of shims .325"
Adjust Buffer Screw
TABLE 1
1. With the engine running at normal operating
5. Connect the booster spring and the stop lever
temperature, turn the buffer screw in (Fig. 8) so that it
spring. Start the engine and recheck the maximum no-
contacts the differential lever as lightly as possible and
load speed.
still eliminates engine roll.
6. If required, add shims to obtain the necessary
NOTE: Do not raise the engine idle
operating speed. For each .001 "in shims added, the
speed more than 15 rpm with the buffer
operating speed will increase approximately 2 rpm.
screw.
IMPORTANT:
If the maximum no-load
2. Hold the buffer screw and tighten the lock nut.
speed is raised or lowered more than 50
rpm by the installation or removal of shims,
Adjust Booster Spring
recheck the governor gap. If readjustment
of the governor gap is required, the position
of the injector racks must be rechecked.
With the idle speed adjusted, adjust the booster spring
as follows:
NOTE: Governor stops are used to limit
1. Move the speed control lever to the idle speed
the compression of the governor spring,
position.
which determines the maximum speed of
the engine.
2. Refer to Fig. 9 and loosen the booster spring
retaining nut on the speed control lever.
Adjust Idle Speed
With the maximum no-load speed properly adjusted,
adjust the idle speed as follows:
Page 99
