DETROIT DIESEL
Engine Tune-Up
required to move the stop lever to the RUN position
10. Use a new gasket and replace the valve rocker
and a deflection in the fuel rod (fuel rod deflection can
cover.
be seen at the bend). If the rack is found to be too
tight, back off the inner adjusting screw slightly and
tighten the outer adjusting screw.
Adjust Maximum No-load Speed
All governors are properly adjusted before leaving the
5. To adjust the remaining injector rack control levers,
factory. However, if the governor has been recondi-
remove the clevis pin from the fuel rod and the
tioned or replaced, and to ensure the engine speed will
injector control tube lever, hold the injector control
not exceed the recommended no-load speed as given
racks in the full-fuel position by means of the lever on
on the option plate, the maximum no-load speed may
the end of the control tube. Turn down the inner
be set as follows:
adjusting screw on the injector rack control lever of
the adjacent injector until the injector rack has moved
Start the engine and, after it reaches normal operating
into the full-fuel position and the inner adjusting
temperature, determine the maximum no-load speed
screw is bottomed on the injector control tube. Turn
of the engine with an accurate tachometer. Then stop
the outer adjusting screw down until it bottoms lightly
the engine and make the following adjustments, if
on the injector control tube. Then alternately tighten
required.
both the inner and outer adjusting screws.
1. Refer to Fig. 8 and disconnect the booster spring
6. Recheck the rear injector rack to be sure that it has
and the stop lever retracting spring.
remained snug on the ball end of the rack control
lever while adjusting the adjacent injector rack. If the
2. Remove the variable speed spring housing and the
rack of the rear injector has become loose, back off the
variable speed spring retainer located inside of the
inner adjusting screw slightly on the adjacent injector`
housing.
rack control lever and tighten the outer adjusting
screw. When the settings are correct, the racks of both
3. Refer to Table I and determine the stops or shims
injectors must be snug on the ball end of their
required for the desired full-load speed. Do not use
respective control levers.
more than four thick and one thin shim. A split stop
can only be used with a solid stop (Fig. 5).
7. Position the remaining injector rack control levers
as outlined in Steps 4, 5 and 6.
4. Install the variable speed spring retainer and
housing and tighten the two bolts.
8. When all of the injector rack control levers are
5. Connect the booster spring and stop lever spring.
adjusted, recheck their settings. With the control tube
Start the engine and recheck the maximum no-load
lever in the full-fuel position, check each control rack
speed.
as in Step 4. All of the control racks must have the
same "spring * condition with the control tube lever in
6. If required, add shims to obtain the necessary
the full-fuel position.
operating speed. For each .001" in shims added, the
operating speed will increase approximately 2 rpm.
9. Insert the clevis pin in the fuel rod and the injector
control tube levers.
IMPORTANT: If the maximum no-load speed is
raised or lowered more than 50 rpm by the
STOPS
Full Load Speed
SHIMS
Split Ring
RPM
Solid Ring
2575-2800
0
0
A s Required
A s Required
2101-2575
1
0
As Required
1701-2100
1
1
1200-1700
1
2
A s Required
TABLE 1
Fig. 5 - Locating of Shims and Stops
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