1972 25hp evinrude overheating

ok so I have a 1972 25hp evinrude that is overheating. I have replaced the water pump, put in a new thermostat, and have forced water through the cooling system and it circulates through the powerhead and around the cylinders with ease. I read somewhere that there could be a clog in my manifold or a blown manifold gasket. I have however replaced my head gasket. Is this the same thing? and what else should I try because it is still overheating. I could fry an egg on it!

Thanks!

Re: 1972 25hp evinrude overheating

Welcome to the site! Now to your problem, is your impeller pumping water? I ask because when i replaced my impeller on my 73 25hp i snapped a screw, and thought that just two would hold a seal, and it wouldnt. I never ran it as hot as you are describing, i am pretty sure its not good to run them that hot. I ended up having to drill it out and re tap it. Hopefully nothing got warped from the temp. Why was the headgasket replaced?

Re: 1972 25hp evinrude overheating

Item #6, part number 313435, Restrictor. It is melted from prior overheating. It is made of plastic. You have to remove the powerhead for access. While you have it off, replace the exhaust cover gaskets. Head gasket and exhaust gaskets should always be replaced on any motor that has been overheated, or they WILL leak.

Re: 1972 25hp evinrude overheating

F_R:
Well replaced the head gasket because when I was looking at the cylinders and pistons I noticed that the orgininal head gasket had dry rotted and crumbled away.

outlawfox13
I will order the part number 6 like you said and replace the exhaust gaskets. Is there anything in the head itself or the manifold that could be clogging up too? and if you look at the link below,this is how the water comes out of mine too, is this normal?. his motor is almost identical to mine.

Thanks for the feedback guys!

Re: 1972 25hp evinrude overheating

This is how my motor shoots out water, is this normal?

http://www.youtube.com/watch?v=qp8_hYGyR-8

Re: 1972 25hp evinrude overheating

Yes

Re: 1972 25hp evinrude overheating

Happy New Year to the members of the forum

I came upon this thread while working on 1976 Johnson Evinrude 20 HP.

This summer I acquired two old outboards full of parts. The most promissing was the 1976 20 HP evinrude. The outboard came in a variety of boxes as it was partly disassembled. The project was started back this summer and it has been long and tidious at times as the engine was stored for many years. After managing to remove the engine from the lower unit I noticed that the exhaust restrictor was partly melted ( see attached photo). I suspect there must have been an overheating problem. The engine block is the next part of the project. It is not seized.

I hoping to have the engine fully restored to fit on a transom of a 14 foot zodiac

I would like to know the importance of the role of the restrictor. What would be the outcome if it was not replaced?
Why is it made of plastic and not copper or aluminum?

Second question.

Some of the rubberized mount(vibration dampers) in some cases are cracking and delaminating. I believe most are now obsolete. How to make sure a mount is worth putting back on? How much flexibility should they have?

Third question.

Is "Never Seeze" a good choice when reassembling the outboard. The tare down process was very frustrating at times because various bolts sheared inside the casting threads which required drilling and re-tapping.

Any advice would be appreciated

Terry