3500 Vehicular Engines Caterpillar

Illustration 1	g00868655
3161 Governor (typical example) (1) Manual speed setting control (2) Speed adjusting motor head (3) External droop adjustment

The 3161 Governor is a hydromechanical governor. The 3161 Governor is connected to the engine fuel system by a mechanical linkage. The governor controls the rate of fuel that is injected into each of the engine cylinders in order to adjust for engine loads.

The speed adjusting motor is located on the governor cover and runs on 24 VDC power supply. When the motor is actuated, the motor rotates a speed adjustment screw in order to adjust the position of the governor speed adjusting lever.

The 3161 Governor has a maximum of 11 N·m (9 lb ft) of torque output over the full 42 degrees of terminal shaft rotation while the fuel is in the ON direction and the OFF directions. The governor terminal shafts are moved in both directions by hydraulic pressure. No return spring is used on the outside of the governor. The return spring is located on the inside of the governor. This spring will cause the terminal shafts to rotate to the full shutoff position when the governor is not in operation.

The recommended travel (rotation) of the terminal shafts is approximately 30 degrees from low idle to full load. The following results will take place:

• There will be extra play at each end of the terminal shafts.

• The governor will make a complete shutdown.

• The maximum amount of fuel will be provided.

The 3161 Governor is connected to the engine oil system. The pressurized engine oil supply is sent to the governor through an orifice and through internal passages. The governor maintains the correct oil level and the governor will drain excess oil back into the engine. This will give a constant flow of engine oil through the governor.

The governor must be filled with approximately 1.8 L (1.9 qt) of clean engine oil before engine start-up. Fill the governor with oil if the governor has been removed or if the governor has been overhauled. The oil fill cap on the 3161 Governor is located on the top cover.

Illustration 2	g00868659
Schematic for 3161 Governor (typical example)

3161 Governor

This governor is used with a vehicle that requires a specific torque rise application. The basic governor for this vehicle includes the features that follow:

• Pneumatic speed control

• Fuel ratio control

• Torque rise control (internal feature)

• 24 to 32 VDC "energize to shutdown" solenoid

• Manual shutdown

A cable assembly and a shutdown linkage is used to activate the manual shutdown. The keyswitch on the instrument panel may also be used to activate the shutdown solenoid.

An air line is connected to the governor control valve in the cab. The valve is activated by the throttle foot pedal. This controls governor speed from Low Idle through High Idle.

Refer to Systems Operation, SENR3028, "Caterpillar 3161 Governor" for complete operation and adjustment procedures.

3161 Governor with Torque Rise D11N

This governor is used with a vehicle that requires a specific torque rise application. The basic governor for this vehicle includes the features that follow:

• Fuel ratio control

• Torque rise control (internal feature)

• 24 to 32 VDC "energize to shutdown" solenoid

• Manual shutdown

This governor has a detent for low idle. The governor control lever may be moved past the low idle detent in order to shut off the engine. The keyswitch on the instrument panel may also be used in order to activate the shutdown solenoid.

A lever is connected to the governor control lever and the decelerator control pedal in the cab by a linkage. The governor control lever controls the engine speed from SHUTOFF to HIGH IDLE. The decelerator pedal controls engine speed from high idle to 1000 rpm.

Refer to Systems Operation, SENR3028, "Caterpillar 3161 Governor" for complete operation and adjustment procedures.