Fuel System (Rev 1/97)
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4. With the engine running in high speed, check the
engine speed and adjust as necessary for that particular
unit.
5. With the engine running in high speed, turn the maxi-
mum speed stop screw in (clockwise) until it touches
the governor linkage. The engine speed will decrease
and you will feel resistance when the maximum speed
stop screw begins to contact the governor linkage. Back
the maximum speed stop screw out one turn from the
point where it first touches the governor linkage.
6. Lock the maximum speed stop screw in this position
with the jam nut, replace the cap nut, and install a new
lead seal.
Fuel Limit Screw Adjustment
NOTE: The fuel limit screw is covered with an anti-
tamper cap and is not adjustable on later model engines.
The fuel limit screw is located on the end of the injection
pump governor housing, which faces toward the flywheel.
The fuel limit screw is set when the injection pump is cali-
brated at the factory and SHOULD NOT be adjusted unless
there is reason to believe someone has tampered with it.
Evidence that the fuel adjustment screw has been moved
includes a damaged or missing lead seal, an engine that has
difficulty picking up speed, or an engine that emits exces-
sive amounts of black smoke when the engine changes
speed. Use the following procedure to adjust the fuel limit
screw.
NOTE: Two adjustments are required to adjust the fuel
limit screw properly. First the fuel limit screw assembly
must be removed from the governor housing to adjust the
plunger clearance. The fuel limit screw assembly can then
be replaced and adjusted correctly.
Adjust Plunger Clearance
1. Remove the lead seal and the cap nut from the fuel
adjustment screw.
Fuel Limit Screw Location
2. Loosen the lock nut and remove the fuel limit screw
assembly from the governor housing.
Fuel Limit Screw Assembly
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