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