A
penile prosthesis is provided, which includes at least one cylinder, a reservoir, and a pump including a pump housing, at least one reservoir channel fluidly
coupling the pump housing to the reservoir, at least one cylinder tube fluidly connecting the pump housing to the cylinders, and a fluid passageway fluidly coupled to the cylinder tube and a transfer chamber. The pump further includes a first poppet and a second poppet, each of which is biased toward its respective
valve seat within the fluid passageway. A bypass chamber is fluidly connected to the fluid passageway by a bypass input channel and a bypass output channel. The bypass chamber comprises a bypass
check valve biased toward a closed position. The pump also includes a pump
bulb fluidly connected to the fluid passageway between the bypass input channel and bypass output channel along the length of the fluid passageway.