DETROIT DIESEL
Engine Tune-UP
establish a guide for adjusting the remaining injector
the cap toward the plunger will force the oil from the
rack control levers.
gap in the form of a small bead.
7. Hold the gap adjusting screw and tighten the lock
1. Disconnect any linkage attached to the speed control
nut.
lever.
8. Recheck the gap and readjust if necessary.
2. Turn the idle speed adjusting screw until 1/2" of
the threads (12-14 threads) project from the lock nut,
9. Stop the engine and, using a new gasket, install the
when the nut is against the high-speed plunger.
governor cover. The governor cover should be placed
on the housing with the pin of the speed control lever
CAUTION: A false fuel rack setting may result
projecting into the slot of the differential lever.
if the idle speed adjusting screw is not backed
out as noted above.
10. Install the screws and lock washers finger tight. Pull
the cover away from the engine and tighten the
NOTE: This adjustment lowers the tension of
screws. This step will properly locate the cover on the
the low-speed spring so it can be easily
governor housing.
compressed. This permits closing the low speed
gap without bending the fuel rods or causing
the yield mechanism springs to yield or stretch.
Position Injector Rack Control Levers
3. Back out the buffer screw approximately 5/8", if it
The position of the injector racks must be correctly set
has not already been done.
in relation to the governor. Their position determines
the amount of fuel injected into each cylinder and
4. Loosen all of the inner and outer injector rack
ensures equal distribution of the load. Properly
control lever adjusting screws (Fig. 2). Be sure all of
positioned injector rack control levers with the engine
the levers are free on the injector control tube.
at full-load will result in the following:
5. Move the speed control lever to the maximum speed
1. Speed control lever at the full-fuel position.
position. Turn the inner adjusting screw down on the
rear injector rack control lever until a step-up in effort
2. Governor low-speed gap closed.
is noted. This will place the rear injector rack in the
full-fuel position. Turn down the outer adjusting screw
3. High-speed spring plunger on the seat in the
until it bottoms lightly on the injector control tube.
governor control housing.
Then alternately tighten both the inner and outer
adjusting screws. This should result in placing the
4. Injector racks in the full-fuel position.
governor linkage and control tube assembly in the
Adjust the rear injector rack control lever first to
Fig. 3 - Checking Rotating Movement of
Fig. 4 - Checking Injector Rack "Sgring"
Injector Control Rack
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