DETROIT DIESEL
Engine Tune-Up
required to move the stop lever to the RUN position and
10. Use a new gasket and replace the valve rocker
a deflection in the fuel rod (fuel rod deflection can be
cover.
seen at the bend). If the rack is found to be too tight,
back off the inner adjusting screw slightly and tighten
Adjust Maximum No-Load Speed
the outer adjusting screw.
All governors are properly adjusted before leaving the
5. To adjust the remaining injector rack control levers,
factory.
However, if the governor has been
remove the clevis pin from the fuel rod and the injector
reconditioned or replaced, and to ensure the engine
control tube lever, hold the injector control racks in the
speed will not exceed the recommended no-load speed
full-fuel position by means of the lever on the end of the
as given on the option plate, the maximum no-load
control tube. Turn down the inner adjusting screw on
speed may be set as follows: Start the engine and, after
the injector rack control lever of the adjacent injector
it reaches normal operating temperature, determine the
until the injector rack has moved into the full-fuel
maximum no-load speed of the engine with an accurate
position and the inner adjusting screw is bottomed on
tachometer. Then stop the engine and make the
the injector control tube. Turn the outer adjusting screw
following adjustments, if required.
down until it bottoms lightly on the injector control tube.
Then alternately tighten both the inner and outer
1. Refer to Fig. 8 and disconnect the booster spring
adjusting screws.
and the stop lever retracting spring.
6. Recheck the rear injector rack to be sure that it has
2. Remove the variable speed spring housing and the
remained snug on the ball end of the rack control lever
variable speed spring retainer located inside of the
while adjusting the adjacent injector rack. If the rack of
housing.
the rear injector has become loose, back off the inner
adjusting screw slightly on the adjacent injector rack
3. Refer to Table 1 and determine the stops or shims
control lever and tighten the outer adjusting screw.
required for the desired full-load speed. Do not use
When the settings are correct, the racks of both injectors
more than four thick and one thin shim. A split stop can
must be snug on the ball end of their respective control
only be used with a solid stop (Fig. 5).
levers.
4. Install the variable speed spring retainer and
7. Position the remaining injector rack control levers as
housing and tighten the two bolts.
outlined in Steps 4, 5 and 6.
5. Connect the booster spring and stop lever spring.
8. When all of the injector rack control levers are
Start the engine and recheck the maximum no-load
adjusted, recheck their settings. With the control tube
speed.
lever in the full-fuel position, check each control rack as
in Step 4. All of the control racks must have the same
6. If required, add shims to obtain the necessary
"spring" condition with the control tube lever in the full-
operating speed. For each .001 " in shims added, the
fuel position.
operating speed will increase approximately 2 rpm.
9. Insert the clevis pin in the fuel rod and the injector
IMPORTANT : If the maximum no-load speed is raised
control tube levers.
or lowered more than 50 rpm by the
Fig. 5 Locating of Shims and Stops
TABLE 1
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