Mayfair Replacement Magnum Heavy Duty Bilge Pump by Johnson Pump The Johnson Pump Magnum Heavy Duty Bilge Pump is a submersible pump designed to meet and exceed the tough demands of commercial and recreational duty. This 2200 GPH pump has a liquid cooled, 12-pole motor with double ball bearings for extended service life. Like other Johnson pumps, this pump has an impeller that is carefully designed and tested to maximize head and flow. The universal base plate and choice of two different ports m