Cartridge Motor - 500GPH - 24VUpgrade the output of your bilge pump in a matter of a few minutes by replacing the cartridge. Cleaning debris from the impeller has never been simpler or easier. Heavy-duty motor with stainless steel shaft for 500 GPH pumps, 24V. Featrues:. 24V, 500GPH replacement/spare motor cartridge for Johnson bilge pumps. Upgrade the output of the bilge pump in a few minutes by simply replacing the cartridge. Cleaning debris from the impeller has never been simpler or easier