Airlock on 2004 Sea Ray Sundancer 240 with a Merccruiser V6

[Casinoguy]

We have a 2004 Sea Ray Sundancer 240 with a Merccruiser V6.
The overheating alarm keeps coming on.
A Marine mechanic thinks it is an airlock problem in the water intake line and when he clears it, it appears to fix the problem as the water starts to flow, however after sitting in the water for an hour it keeps occurring. Has anyone else had this problem and found the cause?

 

[Bt Doctur]

When was the impeller, and manifolds.elbows replaced

 

[Lazy Daze]

(assuming the above is "good", for now)...

The standard drive on that boat was a Bravo III. I would "suspect" that what's going on is a piece of an old impeller has gotten lodged somewhere. Or, at least, this is a logical first place to start. I would open up the t-stat housing and inspect real well as a starting point. Work backwards from there.

FYI... the base engine on that boat was a V8. Did someone swap it to a V6?

 

[JohnnyAlpha]

I would also inspect the transom assembly for “bravoitis” and if the boat is used where marine growth is an issue inspect the water pickup passage in the out drive for growth.