TUBE AS 2354393 - Caterpillar

Shutoff Solenoid
A shutoff solenoid changes electrical input into mechanical output. It is used to move the fuel injection pump rack to the off position.The shutoff solenoid can be activated by any one of the many sources. The most usual are: water temperature contactor, oil pressure switch, overspeed switch and remote manual control switch.The shutoff solenoid can be either the energized to run or the energized to shutoff type as provided with the engine shutoff control logic.Mechanical Oil Pressure And Water Temperature Shutoff
Mechanical Shutoff Group
(1) Oil pressure sensing valve. (2) Tee. (3) Water temperature sensing valve. (4) Shutdown cylinder.The shutdown cylinder (4) is mounted to the rear of the governor housing. The plunger of the cylinder acts on a spring-loaded lever assembly inside the governor housing. When extended, the plunger rotates the lever assembly to allow full movement of the fuel rack. When the plunger is retracted, the lever assembly returns to its original position which moves and holds the fuel rack in the shutoff position.When starting the engine, the knob on shutdown cylinder (4) must be held in to extend the plunger against the lever assembly inside the governor housing. This will rotate the lever assembly to allow full rack movement. After the engine starts and oil pressure is high enough to hold the plunger extended, the knob can be released. Oil pressure will hold the plunger in this position until there is a low oil pressure condition.Under normal operating conditions, pressure oil from the engine oil manifold flows to tee (2). Part of the oil from the tee flows through water temperature sensing valve (3) into the pressure inlet end of oil pressure sensing valve (1) where the oil flow is blocked and the oil pressure is monitored. The other part of the oil flow from tee (2) flows to and through the drain end of the water temperature sensing valve (3) on to shutdown cylinder (4) where the oil flow is blocked and the pressure holds the cylinder plunger extended.When the oil pressure gets too low then the drain end of the oil pressure sensing valve (1) will open causing the pressure oil at shutdown cylinder (4) to drain back to the engine block. With no oil pressure at the shutdown cylinder (4), the lever assembly in the governor returns to its original position pushing the cylinder plunger to the retracted position and moves the fuel rack to the shutoff position to stop the engine.When the water temperature is too high, the pressure oil that flows through water temperature sensing valve (3) is diverted to drain within the valve body and flows back to the engine block. This causes the oil pressure to become too low and the engine will stop as described above.
Find and correct the problem that caused the engine to stop. This will help prevent damage to the engine from not enough lubrication or too much heat.
Water Temperature Switch
Water Temperature SwitchThe contactor switch for water temperature is installed in the water manifold. No