Johnson Pump Electro-Magnetic Bilge Pump Float Switch The Johnson Pump Electro-Magnetic Bilge Pump Float Switch offers a combination of reliable solid state electronics and a sealed float switch. It activates the bilge pump at 2 water level, and deactivates the pump at 34 water level. With high-impact plastic and false start-prevention, this bilge pump float switch is an ideal choice among many and will provide long lasting use and extreme durability. Direct replacement to older Mayfair Electro-