Overheating problem

[MidwestMonaco]

Had my boat out today and I noticed the temp gauge creeping up into the "red" zone. I have had the boat out about 15 other times this summer with no problems.<br /><br />Here is the situation; the temp got high when I was crusing very slowly in a no wake zone for about 5 minutes after putting the boat in the water and just before putting it on the trailer at the end of the day. But once I increase speed the temp goes way down to where it normally is no matter how hard I push the boat. As long as I'm not idiling along it stays cold.<br /><br />Boat is an 84 Sea Ray, with a tired but good running 350 chevy/mercruiser.<br />Any ideas of where to start looking for the problem?

 

[achris]

Re: Overheating problem

Water pump impeller in the leg. When was it last changed?

 

[MidwestMonaco]

Re: Overheating problem

I'm not sure when it was changed, I know the outdrive was rebuilt in 03 right before I bought the boat but that is all I know.

 

[achris]

Re: Overheating problem

Impellers should be checked every year.

 

[rodbolt]

Re: Overheating problem

sounds like the seawater pump is failing. time to put a kit in it. its just not flowing enough water at idle. happens a lot