Overheating 9.9 1980 Johnson

[scully222]

I installed a new water pump on my 1980 9.9hp Johnson, ran it and it appears to be over heating. I am not able to hold my hand on powerhead for more than 30 sec. Water is coming out of pee hole like it should. I thought it might be some crud clogging the thermostat or insides. When I dropped the lower unit the first time I cleaned and scraped a lot of crud from bottom and I thought something might have gone up inside. I opened up engine and took out thermostat and don't see anything unusual. If water is coming out of pee hole, does that mean water is circulating through the powerhead? Should I take all 3 sides off to look around? Change thermostat? Newbie learning.

 

[Rick.]

Re: Overheating 9.9 1980 Johnson

To be honest I don't think you have a cooling problem. You are supposed to be able to hold your hand on the head for a three count. If your getting anywhaere close to thirty your doing great. You can test your stat by putting it in a cup of 160 or higher water and watch to see if it opens. If it does then your safe to assume it is working fine. I have found a new stat may not last as long as a properly operating old one. The tell tale is an indication the water pump is pumping and nothing more. Your power head could be ready to catch fire and the tell tale would still flow. If you want you could flush your power head by dropping the leg and hooking a hose directly to the water tube and letting water flow out the thermostat location(thermostat removed). Sounds like you have a great engine there and also you show an indication that your going to take good care of it. It will last you a good long time. Here is a link I consider a must read for all us 9.9 and 15 OMC owners. Enjoy and best of luck. Rick.

http://www.sschapterpsa.com/ramblings/OMC/OMC info.htm