We only have a switch that cuts the pump off when the engine is not running, but when the engine is running the pump is running at a constant speed. Our water temperature never goes above 170 (running a 270cc Yamaha) measured with an inline sensor and running straight water and during the hot Florida summers. This pump will move about twice the amount of water that the Bosch pump moves.Bob - AGM batteries? Are you just running a switch in-line, and letting the pump run constant speed, draw on battery whatever it is?
Whats wrong with a pump off the rear axle,