874212 Volvo.Penta Lock plate

Illustration 1 g00601233
(1) Oil Pressure Sending Unit.Electrical resistance is used in the sending unit for oil pressure. This sending unit contains a material that changes electrical resistance according to the pressure that is sensed.The sending unit for oil pressure is in a series circuit with the electrical gauge. As the pressure on the sending unit changes, the reading on the gauge changes in the same way. This sending unit requires 24 volts of electrical input. This unit is only used with the protection systems that are energized to run.Water Temperature Sending Unit (WTSU)
Illustration 2 g00601099
Water Temperature Sending Unit (1) Bulb. (2) Nut. (3) Terminal.Electrical resistance is used in the sending unit for water temperature. The sending unit for water temperature is an electrical resistance. This sending unit contains a material that changes electrical resistance according to the temperature that is sensed by bulb (3) .The sending unit is in a series circuit with the electrical gauge. When the temperature is high, the resistance is high. This will create a high reading on the gauge. The sending unit must be in contact with the coolant. If the coolant level is too low the sending unit will not work correctly. The coolant level may be low due to different reasons. One cause of low coolant level is a sudden loss of coolant while the engine is running.This sending unit requires 24 volts of electrical input. This unit is only used with protection systems that are energized to run. Mechanical Gauges For Temperature
In order to check the gauges, place the bulb in a pan of oil. The bulb should not touch the pan. Put a thermometer in the oil in order to measure the temperature. Compare the temperature on the thermometer with the temperature on the direct reading.Mechanical Gauges For Oil Pressure
In order to check the gauges, connect the gauge to a pressure source that can be measured with accuracy. Compare the pressure on the gauge of the test equipment to the pressure on the direct reading.Contactor Switch For Water Temperature
The following tools are needed:
Fabricated heat sink
2F-7112 Thermometer
3J-5389 Plug
8T-0500 Continuity Tester
Make a heat sink. The material can be brass, steel, or cast iron. Drill a 17.8 mm (0.7 inch) hole through the plate. Use a tap to make 1/2 inch NPT threads.
Make a mark on the two wires for the contactor. The wires for the contactor connect the contactor to the circuit. Disconnect the two wires.
Remove the contactor and install a 3J-5389 Plug. Install the contactor switch in the heat sink.
Place the heat sink and the contactor in water. Use blocks to support the heat sink at surface level.
Connect the 8T-0500 Continuity Tester between the wires for the contactor.
Illustration 3 g00580278
Put the 2F-7112 Thermometer in the water.
Use a torch to heat the water. Heat the water to the temperature that will activate the contactor. The circuit test light should illuminate when the temperature that is in the specifications is reached. If this does not happen, replace the contactor.
Allow the temperature of the water to lower. The circuit test light should go out when the temperature that is in the specifications is reached. If this does not happen, replace the contactor.Overspeed Contactor Switch
The following tools are needed:
6B-0344 Drive Adapter
5L-8184 Drive
6V-7800 Digital Multimeter
Install the 6B-0344 Drive Adapter between the drive and the overspeed contactor. On G3408 Engines, the 5L-8184 Drive must also be installed between the 6B-0344 Drive Adapter and the overspeed contactor. The 5L-8184 Drive has a ratio of one to one. This drive is used in order to provide clearance for the overspeed contactor on the G3408 Engine.
Determine the overspeed setting with the following chart. For a rated speed that is not shown in the chart, use the following equation. 118% of rated speed 25 rpm.
Table 1
Engine Rated Speed     Overspeed Setting 25 rpm     One-half Of Overspeed Setting 12 rpm    
900     1062     531    
1000     1180     590    
1200     1416     708    
1225     1445     723    
1300     1534     767    
1500     1770     885    
1800     2124     1062    
Identify the wires from the common terminal and the normally open terminal. Disconnect these wires. Insulate each disconnected wire with tape.
Reset the overspeed contactor. Press the button that is on top of the case for the overspeed contactor.
Connect the 6V-7800 Digital Multimeter to the common terminal and the normally open terminal. If there is continuity, replace the overspeed contactor.
Illustration 4 g00580281
Remove the tag wire and loosen three lock screws (1). Turn the base of the contactor in the counterclockwise direction. Turn the base until the end of the slots for the screw are against the lock screws.
Start the engine. Use a tachometer that is accurate to 1%. Run the engine to one-half of the overspeed setting.
Turn the case for the contactor in the clockwise direction. Turn this case until the relay for the overspeed contactor trips. This will be indicated by a reading on the 6V-7800 Digital Multimeter. The reading on the multimeter will be between the common terminal and the normally open terminal. If the overspeed contactor is turned all the way in the clockwise direction, and the multimeter shows no continuity, replace the overspeed