I have a 50hp Tohatsu that I have just changed out the water impeller. I know that it is installed correctly for I have done this on a yearly time frame and I double check it. I just started getting a high heat warning. This was my next trip to water with it. I put a low water pickup on it 6 years ago. With the motor in water and at idle I have a strong suction from the pickup, tested with my hand. My oil to gas mix is correct. I can find no fuel leaks. The water port on the side is giving off a solid stream of water, which is much warmer than usual when the alarm and light go off. Could this be the thermostat or could I have suck something up into the low water pickup? Is the latter even possible? I do fish a lot of shallow saltwater.