The governor method eliminates the PTO overspeed problems. The main advantage lies in the fact that the driver
cannot physically overspeed the components, since the engine -RPM is limited during PTO operation mode. This method
does require the addition of a few components to the truck. For the CCE-IHC dump truck application with the air operated
PTO system, the added parts include only a new air line and an air cylinder and mounting hardware. The governor
method involves adding a Manual Variable Speed (MVS) Governor (see Figure 2) on the engine throttle control lever at
the engine fuel rump and preventing speeding of the engine in excess of the recommended speed setting. The Army's
CCE-IHC dump truck is equipped with an air control in the cab for driver engagement of the PTO. This air control
furnishes air for the PTO shift air cylinder. The MVS governor is added by (1) installing a T-fitting in the PTO air line
between the PTO dash control and the PTO shift air cylinder, (2) running an added air line over to the engines fuel pump
rack control, and (3) adding a small air cylinder with adjustable mount to stop the fuel control lever. The mechanic sets
the air cylinder to restrict the fuel pump lever arc to a maximum of 1500 RPM with air pressure supplied when the PTO
control is "ON" and insures there is no lever arc travel interference when the PTO control is "OFF". A return spring in the
air cylinder automatically retracts the piston, allowing unrestricted, full travel of the fuel pump control lever. The normal
size of the air cylinder used is the 4 inch length having a 1 inch diameter piston.
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