DETROIT DIESEL
Engine Tune-Up
Fig. 3 - Adjusting Length of Fuel Rod
joint or end bearing and the terminal lever clamping bolt securely.
NOTE: It will be necessary to slide the terminal lever partially off of the shaft to
attach the fuel rod end bearing or ball joint to the terminal lever.
6. Hold the terminal lever in the full-fuel position and loosen the inner adjusting screw 1/8 of a turn and tighten the outer
adjusting screw 1/8 of a turn to retain the adjustment. This is done to prevent the governor from bottoming the injector
racks, since there is no load limit screw on this governor.
7. Remove the clevis pin between the fuel rod and the injector control tube lever.
NOTE: Cover the cylinder head oil drain back hole, located under the control
lever, when removing the fuel rod clevis pin to prevent its loss and possible
damage to the engine.
8. Manually hold the rear injector in the full-fuel position and turn down the inner rack control lever adjusting screw of
the adjacent injector until the injector rack of the adjacent injector has moved into the full-fuel position and the inner
adjusting screw is bottomed on the injector control tube. Turn the outer adjusting screw down until it bottoms lightly on
the injector control tube. Then alternately tighten both the inner and outer rack control lever adjusting screws.
Fig. 4 - Adjusting Droop Bracket
9. Recheck the rear injector fuel rack to be sure that it has remained snug on the ball end of the rack control lever while
adjusting the adjacent injector. If the rack of the rear injector has become loose, back off slightly on the inner adjusting
screw on the adjacent injector rack control lever. Tighten the outer adjusting screw. When the settings are correct, the
racks of both injectors must be snug on the ball end of their respective rack control levers.
10. Position the remaining rack control levers as outlined in Steps 8 and 9.
11. Insert the clevis pin between the fuel rod and the injector control tube lever.
12. Install the terminal lever return spring.
Adjust Speed Droop
The purpose of adjusting the speed droop is to establish a definite engine speed at no load with a given speed at rated
full load.
The governor droop is set at the factory and further adjustment should be unnecessary. However, if the governor has
had major repairs, the speed droop should be readjusted.
The best method of determining the engine speed is with an accurate hand tachometer.
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