DETROIT DIESEL
Engine Tune-Up
Fig. 7 - Adjusting Buffer Screw
previously performed, to the minimum by backing off
the outer lock nut (Fig. 8) until the end of the booster
spring eye bolt is flush with the end of the nut.
Fig. 8 - Adjusting Booster Spring
3. Adjust the eye bolt in the slot in the bracket so that
an imaginary line through the booster spring will align
Adjust Engine Speed Droop
with an imaginary center line through the speed
control shaft. Secure the lock nuts on the eye bolt to
The adjustment of the spring tension as outlined under
retain the adjustment.
Adjust Variable Speed Spring Tension will result in
approximately 7% droop from the maximum no-load
speed to the full-load speed. This is the optimum
4. Move the speed control lever to the maximum speed
droop setting for most applications. However, the
position and note the force required. To reduce the
droop may be changed as necessary for a particular
force, back off the inner lock nut and tighten the outer
engine application.
lock nut to increase the tension on the booster spring.
1. Lower the speed droop by increasing the spring
tension..
NOTE: Before tightening the lock nuts, reposi-
tion the booster spring as in Step 3.
2. Raise the speed droop by decreasing the spring
tension.
The setting is correct when the speed control lever can
be moved from the idle speed position to the
NOTE: A change in the variable speed spring
maximum speed position with a constant force, while
tension will change the maximum no-load speed
the engine is running, and when released it will return
and the engine idle speed which must also be
to the idle speed position.
readjusted.
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