Abstract: An engine protection device which has a valve assembly supplying engine oil to an hydraulic cylinder which in turn is attached to the throttle of an internal combustion engine or governor of a stationary engine. If the oil pressure drops below a predetermined level, a sensor in the valve unit will cause the oil to drain from the hydraulic cylinder so as to slow down or stop the operation of the engine. In addition to using the oil of the engine itself, air or gas can also be used.

Abstract: This is an improved engine protection device that allows activation of the engine protection device a selected oil pressure and to provide a close pressure for downshifting or shut down to idle. Further, the system may be used to also control the engine speed due to cooling water conditions. The improved device includes an oil pressure regulator having a fluid release system including a reduced pressure feed back system to vary the return pressure to a higher pressure after initial operation at a lower pressure.

Abstract: An engine protection device to automatically reduce engine speed to low idle or complete stop. Engine speed reduction is accomplished through the instrumentalies associated with the engine throttle rod. The effective length of the engine rod varies in response to an increase in the coolant temperature or a decrease engine oil pressure.