Abstract: In a positive displacement variable stroke motor, a constant speed variable power drive governor is disclosed which varies stroke instead of driving pressure and hence conserves power through reducing throttling losses. Typically, the control is used on at least one of a plurality of motors all driven from the high pressure manifold of a pressure compensated controlled pump driven by a prime mover. The particular controlled positive displacement variable stroke motor is connected at fluid intake to the high pressure manifold on the high pressure fluid side and discharges to a reservoir on the low pressure fluid side. The controlled motor also drives a small positive displacement pump--typically an in situ charge pump--and produces a discharge through a square edge orifice in an insolated hydraulic control circuit. In response to load changes, a hydraulic amplifier monitors the pressure in the hydraulic control circuit and changes the motor stroke, typically by changing tilt box angle.