INJECTOR CONTROL TUBE
FUEL INJECTOR CONTROL TUBE
The fuel injector control-tube assembly (Fig. 1) is mounted on the cylinder head and consists of a control tube,
injector rack-control levers, a return spring, and injector control-tube lever mounted in two bracket and bearing
assemblies attached to the cylinder head.
The injector rack-control levers connect with the fuel injector control racks and are held in position on the
control tube with two adjusting screws. The return spring enables the rack levers to return to the no-fuel posi-
tion. The injector control-tube lever is pinned to the end of the control tube and connects with the fuel rod
which connects with the engine governor. Refer to Engine Tuneup for positioning of the injector rack-control
Certain engines use a spring-loaded injector control-tube assembly (Fig. 2), similar to the above except it has a
yield spring at each injector rack- control lever and only one screw and lock nut to keep each injector rack
properly positioned. This enables an engine to be brought to a lesser fuel position if there is an inoperative fuel
injector rack, whereas with the non-spring loaded two screw injector control tube this could not be done. The
above also permits the use of an air inlet housing with no emergency air shut-off valve as is required in some
Do not replace the spring-loaded fuel injector control tube and lever
assembly with the two screw design control tube assembly without
including an air inlet housing that incorporates an emergency air shut-off
valve. However, when the spring-loaded fuel injector control tube and
lever assembly is installed on an engine and the emergency shutdown
mechanism is removed from the air inlet housing, the shaft holes at
each end of the housing must be plugged. Ream the shaft holes to
0.6290 inch and install a 5/8-inch cup plug at each end of the housing.
Engine shutdown (normal or emergency) is accomplished on the spring-loaded fuel injector control tube (one
screw design) by pulling the governor shutdown lever to the no-fuel position. With the two screw design injector
control tube and lever assembly, emergency engine shutdown is accomplished by tripping the air shut-off valve
in the air inlet housing. Normal shutdown is accomplished by pulling the governor shutdown lever to the no-fuel
position. Adjustment of the single screw and lock nut on each injector rack-control lever can be performed the
same as for the two screw design rack-control lever as outlined in Engine Tuneup.
Remove Injector Control Tube
1. Remove the cotter pin and clevis pin connecting the fuel rod to the injector tube-control lever.
2. Remove the two attaching bolts and lock washers at each bracket. Disengage the rack levers from the
injector control racks and lift the control tube assembly from the cylinder head.
Disassemble Injector Control Tube
The injector control tube, one mounting bracket, a spacer, and injector control-tube lever are available as a
service assembly. When any part of this assembly needs replacing, it is recommended the complete service
assembly be replaced. Therefore, the