This fuel feed pump draws diesel from the tank and delivers it to the injection system at the required pressure. It is mounted on the engine block and is driven by the engine camshaft via a lever. The pump contains an internal diaphragm or piston that creates suction on the intake stroke and pushes fuel toward the injection pump on the delivery stroke. A worn pump will cause hard starting, loss of power, or engine stalling under load. The original manufacturer's pump matches the lever geometry and mounting flange dimensions of the engine it was designed for, ensuring correct stroke length and no binding on the cam lobe. When replacing, transfer the lever and gasket from the old unit, and torque the mounting bolts to specification.