1985 Evinrude 9.9 Overheating

I am working on an 1985 Evinrude 9.9 that has overheated and started to smoke. It was shut down. Looks like it was hot enough to start paint peeling at the top of the cylinder head.
It is pumping water through, although the stream is not as strong as on some I have worked on. I replaced the water pump impellers (I think the original was indeed okay) but found the grommet from the pump to the copper water line chipped away, so I thought this was leaking water right back into the exhaust housing, not making it up into the engine. Replaced the grommet.
Running at low speed in a barrel, the temperature remains reasonable. I can put my hand on a warm-to-the-touch block.
I put the engine back on the boat and took it out for high a high speed run. It still wants to overheat. Touching the block after high speed? It is very hot to the touch. The water coming out of the exhaust is hot. The water coming out of the tell-tale is just warm.
So, Do you think I am to the point where I have to pull the power head and check the complete water path from copper tube into the block? I am afraid of this for I do not want to break any bolts ....
Does anything else come to mind that I am overlooking?
Thank you,
J

Re: 1985 Evinrude 9.9 Overheating

Pull the power head and check/replace the upper water pipe grommet.

Re: 1985 Evinrude 9.9 Overheating

Agree with above. I would also suggest checking your compression after a severe overheat. If you need to remove the head there are water passages you con have a look at when it's off. Best of luck. Rick.

Re: 1985 Evinrude 9.9 Overheating

Thank you. I am going to pull the engine today to get at the bottom end.

I did pull the cylinder head and thermostat. I found a water passage partially blocked, a 3 mm diameter or so hole in the thermostat cover. Reemed it out. The thermostat is old and cruddy so I left it out. I took the engine for another ride. Still over heating.

Compression, although not tested, seems to be good as the engine starts and runs well. I will test to be complete.

Thank you.
J

Re: 1985 Evinrude 9.9 Overheating

Do not run without thermostat in place, unless for a short test! You get an air pocket and partial overheat on top.

Re: 1985 Evinrude 9.9 Overheating

As for the grommet problem, you may want to try a quickie that I have used some times.
Take a curtain spring, attach to a battery drill and run up the water tube. If you bend the tip a little up it might cut through the deformed grommet and open it up.

But be careful, this is not a general recommended way of solving the problem!! It is a risk that rubber pieces might block some cooling channel.

Re: 1985 Evinrude 9.9 Overheating

This is all good. Thank you!

I may have found the root cause. I was able to pull the bolts out of the exhaust tube without shearing them off. Good news.

And, the upper water tube grommet is a complete mess; squashed, collapsed on itself, brittle, etc. Probably been this way for a while.....

The grommet is definitely impinging the water flow.

I will try compressed air through the block while I have it out, but I really believe this grommet is the root cause of the problem.

Kudos Haffiman! Thank you!
J

Re: 1985 Evinrude 9.9 Overheating

Quite a common problem.
Good luck with the rest.

Re: 1985 Evinrude 9.9 Overheating

i had the same problem with upper water pipe gromet. i found this problem in 3 motors i was working on.

in the last motor i just puled of water jacket side panels.
ithera rre 2 gasket with small holes in it.
under this gasket, just in block chamber, where water acumulates i found rubber piece, i think it comes from upper gromet.

this rubber piece was just floating in this chamberif this chamber fils with water at aupper part is a hole leting water flow to refile cylinder cooling chanels.this hole is a 6mm diameter
in my opinion when powerhead is of just take out water cower to put new gaskets.