Still having problems with our boat. (1 Mercury 75 Horse. We changed the thermostat and rebuillt the water pump and cleaned up the housing with very fine sand paper. Problem is the warning system is still sounding a steady shrill noise after 1hr and 20 minutes. I have called several people some say no its definitely not your heat censor and others say it is. Please help us in any way you can.<br />Bonnie
