Abstract: Disclosed herein is a fuel metering pump for delivering fuel to rocket or jet engine having a motor driven face cam and a pair of reciprocating rolling diaphragm pump mechanisms movable through opposite suction and pump strokes. The face cam has a ramping cam surface that extends radially more than 180 degrees. This permits both pump mechanisms to be simultaneously in the pump stroke for a portion of the pump stroke so that they alternately reciprocate through the suction and pump strokes at essentially a constant velocity, thereby providing an essentially non-pulsating flow of fuel to the engine.