PIN 6V4186 - Caterpillar

General
Emergency shutoff devices stop the engine when operating conditions are such that engine damage may result if operation is continued. If a shutoff device has stopped the engine, see the topic ALARM SWITCHES for an aid in troubleshooting. Additional measures may be required depending upon the circumstances and conditions present. Authorized dealer personnel should analyze major engine problems.Familiarize yourself with the types and locations of the shutoff devices on your engine, the conditions which can cause each control to function, and the resetting procedures required to start your engine.Have all shutoff controls on the engine checked twice a year by your Caterpillar dealer. To test the devices, abnormal operating conditions must be simulated which could cause engine damage if the tests are incorrectly performed.
If severe or prolonged overheating of the engine has occurred, contact your Caterpillar dealer to have your engine checked for damage.
Always determine the cause of the shutdown, and have the necessary repairs made before restarting your engine.
Electric Shutoff Controls
The operation of all electric shutoff controls is similar: A critical operating condition actuates a switch in the sensing unit of the electric shutoff control. The switch closes the circuit to the shutoff solenoid which moves linkage to bypass the fuel to the cylinders; thus stopping the engine. The shutoff control may require resetting before the engine can start.High Water Temperature Shutoff
The shutoff switch is located in the water temperature regulator housing. Excessive water temperature closes the switch. No resetting procedure is required: As the coolant cools, the switch opens.
The sensing element must be submerged in the coolant to operate. A low coolant level cannot actuate the shutoff.
Low Oil Pressure Shutoff Switch
This device is usually mounted on the side of the engine with oil lines connected to the switch. Low oil pressure closes the switch.Manually operated systems require resetting by pushing the button on the switch until it latches. After the engine is started and oil pressure builds, the knob will return to the extended position.
This switch cannot provide protection if the reset knob does not move to the extended position after the engine starts.
Automatic start-stop systems use a switch which resets itself.Overspeed Shutoff Switch (Electro-Mechanical)
This switch is mounted either on the tachometer drive or on the governor. Excessive engine speed closes a switch by centrifugal force. To reset the switch, push the button marked RESET. The knob will remain down until the engine overspeeds. Overspeed Shutoff Switch (Electronic)
This switch uses a flywheel housing mounted magnetic pickup to sense engine speed. The control box is mounted on the engine block. Excessive engine speed closes a circuit breaker. To reset switch, push arm of breaker to the run position. Fuel/Oil Pressure Switch
This switch is mounted in the fuel manifold between the clean side of the fuel filter and the fuel injection pump housing. Low fuel pressure (below 3 PSI, 2 kg/cm2) opens the switch after the engine has been stopped by one of the above shutoff controls. This switch prevents the battery from discharging after the engine is