Abstract: A fluid pumping system for an engine or other system which reduces the high speed driving power consumption by hydraulic unloading of the mechanically-driven pump element through the use of recirculation through a jet pump when a system fluid pressure target value is achieved. A pressure-activated flow control valve is utilized to efficiently recycle excessive flow volume from the pump through the jet pump and back to the pump's intake with minimized pressure loss, thereby hydraulically unloading the pump in comparison with conventional systems. Energy conservation by the jet pump and recirculation conduit acts to also prevent cavitation of the hydraulically unloaded pump element at high speeds. The fluid system is useful in conjunction with an engine balance shaft system to control gear rattle at low speeds without adding undue gear loads at high speeds.