# Overheating



## jcreamer (Mar 6, 2001)

Neighbor has a 1989 regal 2ok foot boat that idles great and runs great at low rpms. 
When pwr is applied and at higher rpms it overheats.
The out drive has been checked, all the connectors have been checked, and the problem is still there.
He can putt around the water at low rpms and no prob.
When he applies power and brings it up to speed the thing overheats. It is a nice boat but this problem is getting in his nerves.

Any suggestions.


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## jcreamer (Mar 6, 2001)

Didn" mention that it is an inboard (4cyl).


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## tlustyp (Aug 18, 2004)

It sounds like a classic symptom of a poor water pump. I am not that hip to inboards but for outboards when the impellar is bad it works fine at low speeds but does not pump enough water at high rpms.


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## Capt.Skid (Mar 12, 2006)

*Running Hot!*

Sounds more like a exhaust manifold mostly plugged up. Did u change the thermostat? Could be the problem. Not too many things that could cause it to run hot. Usually the pump in the outdrive works or doesn`t work, no in-between!
I would be leaning toward the stat or manifold!

Capt.Skid


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## eba1225 (Oct 15, 2002)

J,

I had that exact problem with my I/O 6cyl. I could putter around all day w/o problems but wind it up and watch the temp rise. 
The solution just what was said in the previous post, replace the manifold. 
I can now fly around w/o a problem.

Erik


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## jcreamer (Mar 6, 2001)

eba1225 said:


> J,
> 
> I had that exact problem with my I/O 6cyl. I could putter around all day w/o problems but wind it up and watch the temp rise.
> The solution just what was said in the previous post, replace the manifold.
> ...


I talked to him and when he had his engine worked on they changed the nanifold and it is not the same one. He ordered the correct manifold and is goiong to try it again.


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## cygnus-x1 (Oct 12, 2005)

My experience is mainly with inboards and in the case of raw water cooling systems it is usually your risers. I assume this I/O is cooled with fresh water / coolant?

If so it would more than likely be in the manifold, water pump, or thermostat (or any combination of the three). When was the last time the water pump / impeller was changed? They need frequent maintenance.


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## jcreamer (Mar 6, 2001)

Found a fix. They are dropping a rebuilt V-6 in it. They took it to the shop and are doing the conversion.


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