Abstract: A centrifugal pump assembly especially adapted for use in conjunction with ink reservoirs of printing press apparatuses. There is provided a centrifugal pump assembly comprising motor mounting means for mounting the motor with respect to the cover member of an ink reservoir. The shaft of the motor extends downwardly into the reservoir and has secured thereto a coupling sleeve. The coupling sleeve includes means for securing the same to the motor shaft and means for releasably engaging the impeller shaft of the pump assembly. The impeller shaft is provided with a positive drive pin adapted to fit into a slot formed in the coupling sleeve to thereby properly align said impeller shaft with respect to the impeller housing and to insure proper positive connection of the impeller shaft with respect to the motor shaft for corresponding rotational movement therewith.