Johnson Pump 4000 GPH Bilge Pump 1-1/2" Discharge Port 12V [40004]Heavy Duty Bilge Pump 4000 Series 12v: The best choice when you are looking for high performance, heavy duty pumps designed to meet and exceed the tough demands of commercial and recreational duty. This pump has a liquid cooled, 12 pole motor with double ball bearings for extended service life. The 2200 motor is sealed off by a mechanical seal design, while the 1600 model has lipseal. The impeller is carefully designed and tested to maximize head and