Mayfair Replacement Johnson Pump Cartridge Bilge Pump Johnson Pump Cartridge Bilge Pumps are direct replacements to the popular Mayfair Cartridge Bilge Pumps and are designed to make cleaning and maintenance easy! Johnson Bilge Pump Cartridges can be removed for cleaning or replacement without the use of a single tool. Lift a tab on the top, give the cartridge a twist, and pull it out thats all there is to it! Johnson Bilge Pump Cartridge includes an all-in-one motorimpeller unit with no loose p