[Dave Murray]

Hi- This is my first post to this board- First I did a search on this subject and read some excellent ideas on similar Yamaha problems. I have a slightly different issue with overheat warning buzzer. This only happens intermitently.Only happens at idle speed.Reverts to normal after two or three minutes- so I can get home OK.So far over two years, have replaced the water pump and both sensors. I don't think the dealer believes this is a problem, but I can't stand not fixing it as I don't trust it anymore. Other than this issue, the engine looks and runs like new. Any technical help would be greatly appreciated. Thanks Dave Murray

[rodbolt]

search more. I have hundreds of posts on your problem

[GeraldBelastock]

Originally posted by rodbolt: search more. I have hundreds of posts on your problem

[GeraldBelastock]

I too have a Yamaha overheating problem. My engine is a 2000 F115 on a 2000 Cobia 184 fishing boat. Overheating occurs at various times intermittently. Sometimes it happens after a few minutes' trolling, other times after a wide-open throttle run. Sometimes the pee stream (telltale) is fine at engine start, but diminishes and stops after a few minutes. Other times the telltale looks fine at low and moderate speed, but seems to DIMINISH at higher speed. I have checked sensor and thermostat, used compressed air to blow out all water hoses and the fuel/cooling water heat exchanger. One thing I have not yet tried is to apply a strong vacuum cleaner to the inlet screens.You say you have many posts on this subject. Is there a "most common" solution or general pattern for solving the problem you can tell us about?

[rodbolt]

have ya tried a careful cleaning of the pressure valve grommet pocket and install a new grommet. also was the rubber dam under the pump wear plate removed and cleaned. both will cause your symptoms. and has the powerhead been replaced with a reman unit?have the t-stats been replaced lately ?