I have a Yamaha Pro 50, I think it is a 1990 or there about. As soon as I turn the key to start it, the warning buzzer on the throttle control goes off. The engine starts fine and there is a good strong stream of water coming out of the tell tale. A friend suggested that it might be the thermostat, so I pulled the thermostat today. It definately needed to be replaced! It was a corroded mess. I pulled it out and cleaned up the corrosion in the housing the best I could. I got a new thermostat and gasket from the local Yamaha dealer. Put it in, started up the engine.. and the buzzer still went off!! I tried letting it flush a couple minutes, restarted, and got the buzzer immediately again. Then I gave up. Could all the gunk and corrosion in the thermostat housing have caused something in the cooling system to clog, or could whatever sends the signal to the buzzer be corroded or disconnected?
