An engine pump is provided which operates with an internal combustion engine or as a supplemental pump or as used in a stand alone device, and includes an internal vent for improved pump and motor durability. The pump is operably and sealably connected to a motor and adapted for connection with a source of fluid and a discharge means. An internal vent is positioned in between an armature shaft of bore along an inlet port thereby decreasing the pressure in the area of the seal. Alternatively, a valve is positioned between the inlet and outlet ports to selectively permit fluid pumped between the inlet and outlet ports to pass through when the outlet port is flow restricted.

 
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> Automatic oil pump, with a valved pumping piston and a valved driving piston unit

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