Overheating Help

[Bert]

My 1999 150 Johnson is overheating on one side. I have put a new waterpump kit in. I removed the head on the side that is overheating and everything seems fine. I took an infared scanner and checked both sides of the motor. One bank of cylinders idles at 160 degrees and the other at 180. It reads the same whether in the water or on the hose. I can run about 10 minutes at 4000 RPM's before the temp alarm sounds. Hope someone has an idea of what to do. The motor came from the coast, so I'm sure it has been in saltwater most of the time.

 

[Bert]

Re: Overheating Help

Forgot to mention that I changed out the thermostats. I have also ran it with and without the thermostats and no changes, one side is always hotter than the other.

 

[outboardnut]

Re: Overheating Help

Are you sure it's the temp alarm and not oil pressure? I believe those make diffrent sounding beeps??

 

[Bert]

Re: Overheating Help

Its not an oil alarm, the infared gun shows the high temperatures.

 

[ezeke]

Re: Overheating Help

Have you tried a salt remover for the cooling circuits? Salt Away or Kwik Tek might help.

http://www.iboats.com/mall/?keyword...=800107502&list_time=1163988708&view_id=21160

 

[clanton]

Re: Overheating Help

Check for correct water pump housing.

 

[Bert]

Re: Overheating Help

Starting to get some results! Took out the thermostats and the voltage regulator, poured vinegar thru the openings a couple of times a day. Started to see sediment and crud coming out. Them I took a pressure washer and flushed thru the regulator opening, lots more crud came out. Started it today and temperatures are running cooler and closer to each other. Going to pull the heads and check them out today. Things are definetly looking better.

 

[Solittle]

Re: Overheating Help

I don't know if your engine has deflectors in the water passages but if it does it would be a good time to replace them when you have the hewads off. The swell over time and can block the water flow.

 

[OBJ]

Re: Overheating Help

Don't think those looper blocks have the deflectors. But it's probably a good ID to pull the heads and clean out any salt/crud build up around the cylinders anyways.

 

[Walker]

Re: Overheating Help

I've used vinegar with great success. I put it in a barrel and run the motor in it til the motor gets up to operating temp. Cut the motor off and let cool. I do this for a couple of days usually running the motor 6-8 times a day.

 

[Melvin Hatcher]

Re: Overheating Help

That would be a whole lot of vinegar.

 

[Walker]

Re: Overheating Help

It is, but it works. You can minimize the vinegar by getting the skeg all the way to the bottom of the barrel.

 

[Bert]

Re: Overheating Help

Ran it today and it never overheated. The temperature fluctuated some while it was running. Maybe something inside, like an old piece of impeller or something . Any ideas of how to get it out without pulling the powerhead.

 

[fishflipper]

Re: Overheating Help

what should the temps be?