Yam 40hp 2cyl Over heat alarm

[andy mcmullan]

Hi from sunny Ireland.<br /><br />My alarm is going off @ 3/4 <br />throttle approximately. The Yamaha dealer has checked the thermostat, changed the sender, checked for salt build up, but it is still happening. On the first run after the sender was changed it ran perfectly at full throttle. The next time I tried it the buzzer sounded again. I don't think the motor is overheating as the power head isn't too hot and my tell-tale is jetting out fine. Could the actual alarm in the control box be defective or is there any thing else I should look at.<br /><br />Cheers<br /><br />Andy