20515177 Volvo.Penta Service cover

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 adjusting screw in order to adjust the position of the governor speed adjusting lever.The manual speed setting control (1) which is located on the front of the governor can be increased or decreased by the engine speed. Turn the manual speed setting control (1) clockwise in order to increase the speed setting. Turn the manual speed setting control (1) counterclockwise in order to decrease the speed setting. The high speed stops and the low speed stops will limit the adjustments.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)
Operation of the 3161 Governor
The 3161 Governor uses engine lubrication oil for the hydraulic system. The pressurized engine oil supply is sent to the governor oil reservoir through an orifice which can be removed from the governor housing for cleaning. First, the oil will travel through internal passages to the suction side of the gerotor pump. The oil will then travel to the pressure side of the gerotor pump as the drive shaft is turned by the engine. An accumulator spring and a piston will keep the pump pressure at approximately 690 kPa (100 psi). The accumulator piston moves upward in the piston cylinder until the pump pressure is 690 kPa (100 psi). The ports in the piston will open in order to control the pump pressure, after the established pump pressure is reached.The pump pressure, which is set by the accumulator, controls the work output of the governor.Increase In Speed Setting
When the speed setting shaft is turned clockwise, the speed