Engine Tune-Up
DETROIT DIESEL
HYDRAULIC GOVERNOR AND INJECTOR RACK CONTROL ADJUSTMENT
IN-LINE ENGINE
The hydraulic governor is mounted on the 3 and 4-53 engines as shown in Fig. 1. The terminal lever return spring and
the fuel rod are attached to an external terminal shaft lever. The maximum fuel position of the governor load limit is
determined by the internal governor terminal lever striking against a boss that projects from the governor cover.
Adjust engines having a hydraulic governor assembly after adjusting the exhaust valve clearance and timing the fuel
injectors.
Adjust Fuel Rod and Injector Rack Control
Lovers
1. Adjust the inner and outer adjusting screws (Fig. 2) on the rear injector rack control lever until both screws are equal
in height and tight on the control tube. Check the clearance between the fuel rod and the cylinder head casting (below the
bolt) for at least 1/16" clearance when the injector rack is in the full- fuel position and the rack adjusting screws are tight.
If the fuel rod contacts the bolt or cylinder head casting, readjust the screws to obtain the 1/16" clearance.
Fig. 1 - Hydraulic Governor Mounted on Engine
NOTE: Overtightening the injector rack control lever adjusting screws during
installation or adjustment can result in damage to the injector control tube. The
recommended torque of the adjusting screws is 24-36 in-lbs (3-4 Nm).
2. Remove the governor terminal lever return spring.
3. Remove the fuel rod end bearing or ball joint from the terminal shaft lever and the terminal lever from the terminal
shaft.
4. Place the terminal lever on the terminal shaft so that the hole for attaching the fuel rod end bearing or ball joint is in
line vertically above the terminal lever shaft at one half the arc of travel. Do not tighten the clamping bolt.
5. Hold the injector rack control tube and the terminal lever in the full-fuel position and adjust the length of the fuel rod
until the end bearing or ball joint will slide freely into the hole of the terminal lever as shown in Fig. 3. Tighten the lock
nut to retain the ball
Fig. 2 - Adjusting Height of Rack Control Lever Adjusting Screws
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