Temp climbing at idle speed

[crazy charlie]

I had this problem last season and here is what I did this winter .Changed o/d water pump kit and base.Cleaned out tstat housing which was not clogged or dirty.Changed stat.Removed and cleaned spring and ball set up on both sides of tstat housing.The temp still climbs when I am at idle.Goes right down if I tap the throttle up a few rpms while idling down a canal or if I throttle up to get on plane .I am about ready to get risers unless a better idea comes up.I am 99% sure the risers are very good though.They were perfect 3 years ago and I always fresh water flush after each use.Any suggestions??Twin 230 xl hp mercruisers with alpha drives.Charlie

 

[Laddies]

Re: Temp climbing at idle speed

The water tube plate on the upper gear case could have a bad gasket or the plastic plate could be warped, the outer hose from the bell hsg. to the gimbal hsg. could be cracked or crimped, the gasket under the w/pump base could be letting exhaust into the pump pick up, but if you remove the input hose from the thermostat hsg. you can compair water flow from 1 engine to the other and see if 1 is lower at idle.

 

[crazy charlie]

Re: Temp climbing at idle speed

Thanks Laddies but all of the above are new or recent.I had the water pump base replaced incase the exhaust was the cause.Comparing the flow couldnt hurt.

 

[Don S]

Re: Temp climbing at idle speed

Does that engine have a power steering cooler between the transom shield and the thermostat housing? If it does, look in the end of the hose and the cooler for excess "Stuff" that shouldn't be there.

 

[crazy charlie]

Re: Temp climbing at idle speed

I have a p/s cooler but I may have to rent a dwarf to get to it.I will try to back flush it.Thanks Don.

 

[Don S]

Re: Temp climbing at idle speed

Backflushing with it all together probably won't do it. You need to pull the hose, then back flush the cooler, then start the engine and check the flow from the hose you took off the cooler. Anything that was still in the hose should flush out.<br />I've found over many year, that the easy stuff is seldom if ever the problem.

 

[crazy charlie]

Re: Temp climbing at idle speed

Well I guess I may have to skip dessert a few nights and squeeze down there.