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