[smanter]

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?

[Elmer Fudge]

Scruffy,you did'nt say the warning buzzer was a constant beeping or one long beeeeep.I am wondering if the buzzer which you're hearing might possible be your low oil warning?.

[rodbolt]

hello scruffy. you have a bad sensor or a short on the pink wire. if the alarm comes on as soon as the keyswitch is turned on with the engine cold. has any other work been done. post how this problem came about. a quick test of the sensors is just unplug them and cycle the keyswitch. if the alarm does not sound it sends you in the right direction. good luck and keep posting

[smanter]

Elmer was right. It was a low oil warning buzzer. I feel pretty stupid for not thinking of that, but I've never let the oil level get low and I didn't even know about this buzzer warning. The oil tank was down to a little less than a quarter full. I filled it up and everything is fine. Took it out for a test run during Thanksgiving and it worked great. Thanks for the help, you saved me a trip to the shop.