HELP! 1983 volvo penta aq225d 280 sterndirve overheating

[markojr]

i just installed a new thermostat and impeller. backwashed the water lines and the engine still overheats.. runs ok at up to 22 rpm under 180 temp when i get to 25 - 30 rpm plus temp gauge goes up to 240 degrees. when i throttle back to 22rpms or less temp gauge drops down to under 180 degrees

Anyone have any other ideas as to what might be causing this issue.

I could use the help.

Thanks so much

 

[JAL51974]

Re: HELP! 1983 volvo penta aq225d 280 sterndirve overheating

Is the 280 equipped with the heat exchanger?
If it is you might check the piping of water from the bay into the heat exchanger- any leaks in that piping will cause temp fluctuations. If its happening when you are on plane like I would assume from your mph, there is a piece called the water neck fitting on the outdrive, that needs good seals to work properly. My 275 outdrive drove me crazy finding this type of leak. Mechanic tested it and couldn't find anything putting pressure on the lines. I finally found the leaking seals doing a suction on those lines. Think I wrote about it here several years ago.