Re: -1959 35hp Thermostat
Fredrik, first let me say that it is extremely unusual for the thermostat to fail in the closed position. They almost always fail in the open position. But if you are convinced that is what damaged your motor, nobody will convince you otherwise.
Nevertheless, the problem with removing it, other than running too cool, is that people remove not only the thermostat, but they also throw away the black housing and check valve. Without those parts, exhaust can travel down the water return tube, back to the water pump, and prevent the pump from working properly. That is what you have been reading about.
Water is pretty cold there in Sweden, isn't it? The thermostat constantly samples the water temperature after it passes through the powerhead and opens or closes as required to maintain proper engine temperature. When it is closed, the water is sent back to the pump for recirculation. This is going on any time the motor is running. In cold water, the thermostat may not open at all at slow idle speeds. Even at higher speeds, it will be opening and or closing.....which may make you think it is not working correctly. With it removed, it is as if wide open all the time, so sure it discharges lots of water.
