Use this procedure when an engine is started for the first time
after work is done on the fuel system or governor.
Disconnect the air inlet system from the turbocharger.
Have a person in position near the turbocharger air inlet
with a piece of steel plate large enough to completely
cover the turbocharger air inlet.
Be careful when plate is put against air inlet opening. Due
to excessive suction, the plate can be pulled quickly
against air inlet opening. To avoid crushed fingers, do not
put fingers between plate and air inlet opening.
Start the engine. If the engine starts to run too fast or
runs out of control, immediately put the steel plate
against the turbocharger air inlet. This will stop the air
supply to the engine, and the engine will stop.
The only "ON-ENGINE" adjustment to the governor is the final
low and high idle settings. A procedure to check the FRC (fuel
ratio control) settings is given in Testing And Adjusting in this
All other governor adjustments (including the
FRC) are to be done "OFF-ENGINE" on the 1U7326
Governor Calibration Bench. Refer to 3114, 3116
& 3126 Governor Service Manual, SENR6454 for
procedures and tooling required to bench test and
adjust the governor.
The fuel setting (rack setting), fuel timing and
performed "ON-ENGINE" and are located under
the valve cover. See the topics Fuel Setting, Fuel
Timing and Injector Synchronization.
(1) FRC (Fuel Ratio Control. (2) Boost line port. (3) Low idle
screw. (4) High idle screw.
Refer to the engine information plate or TMI
Bench Performance Data for the correct low and
high idle speed and fuel setting.
The low idle screw (3) is initially set on the 1U7326 Governor
Calibration Bench. Final low idle adjustment is set with the
governor on the engine. With the engine idling, loosen the
locknut and adjust screw (3) to the specified low idle speed.
Tighten the locknut and recheck the low idle setting.
Older governors require a 1U6672 Wrench to
adjust the low idle screw. Newer governors
require a 13 mm wrench and a 4 mm Allen
The high idle screw (4) is initially set on the 1U7326 Governor
Calibration Bench. Final high idle adjustment is set with the
governor on the engine. With the engine at full throttle and no
load, loosen the locknut and adjust screw (4) to the specified
high idle speed. Tighten the locknut and recheck the high idle