Engine over heat at idle

[capecodcruiser]

Hello all,
one of my engines is will run warm to overheat at idle. Get RPM's up to about 1K and cools right down. Strainer is clear, impellers on raw water pump is good, the rest I am questioning. Trying to figure out a direction to go in. Circulation pump, heat exchanger, T-stat. I would really appreciate any thoughts or comments on what others have encountered. Thank you
(see signature for engine details)

 

[wyrman]

Last summer my bro-in-law's 4 banger did the exact thing and it was the water pump on the engine.
Allthough it is a totally different engine, they all work mostly the same.

 

[Lazy Daze]

How many hoses are on your t-stat housing?

 

[Alegria]

If you have out drives there might be a water pump in the out drive that is not working. My old out drives had a pump In the drive and one on the engine when the drive pump impeller went mine did the same thing.

 

[capecodcruiser]

V drives....Daze, I will look at T-stat and get back to you. Thanks!

 

[Got2Cuff]

Hey, did you ever figure out the problem? I also have 350 Horizon MPI/V drives and started heating up in lower rpm? I just changed out the impeller(s) last season and my port engine isn't pumping out raw water that good. Im thinking it's the heat exchanger???
Thanks,
Mario