OMC 4.3 overheating at idle.

ulster1

Seaman Apprentice
Joined
May 14, 2007
Messages
39
Installed new botton end impellers this season and on the starbord engine I have an overheating problem at idle.
As soon as I increase the RPM's to 1500 the temp drops and she runs at normal op. temp. Go back to idle she overheats again.
It seems that I am not getting enough cooling water from the bottom end impeller??
It was fine last season with the old impeller? what could I have done wrong or what could be the problem.
The exhaust manifold also heats up more than usual how do I test the system to ensure I have enough cooling water.
+===========================================+
Problem #2.
On my port side engine the stat seems to open and not close I removed it and tested it following the proper procedure and it checks out OK.
Just back form installing it again and still have the same problem.
At idle it reached temp-- increase idle it drops the temp down ----(according to the temp gauge) let it idle the temp returns to normal??
 

ulster1

Seaman Apprentice
Joined
May 14, 2007
Messages
39
Re: OMC 4.3 overheating at idle. Please help!!!!

Re: OMC 4.3 overheating at idle. Please help!!!!

I should also point out that I removed the drives for some maintenance during the winter had a little difficulty installing them in the spring however all seemed to go together good ---- I installed new gaskets and pump seals so I am at a loss as to what could be the problem.

Any comments would be appreciated.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,584
Re: OMC 4.3 overheating at idle.

It could be that your risers/manifolds are plugged up or there are other obstructions in the cooling path.
 
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