78 Johnson 35hp - water in combustion chambers after head gasket change

lotsofish

Cadet
Joined
May 25, 2009
Messages
19
I just replaced my head gasket (that was blown), the thermostat, and the water cover gasket on my 78, 35hp johnson.

Hooked it up to the hose and ran it for a bit. It's getting water in the chambers. The head bolts are all tightened properly. Compression is good - 110 on each cylinder. Fresh fuel.

I think maybe the parts store (a local dealer) sold me the wrong head gasket? Could I have good compression and still let water leak in, or could the water be coming from somewhere else?

This is the head gasket I was sold:
http://www.iboats.com/Head-Gasket-f...2340419--**********.251058620--view_id.173729
But after I looked at shop.evinrude.com, I think I should have this one:
http://www.iboats.com/Head-Gasket-f...2340419--**********.251058620--view_id.173739

The bolts all line up (again compression is good), but the one I have has a couple small openings that go to the water cover area, bypassing the thermostat. I didn't think it was a big deal.
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: 78 Johnson 35hp - water in combustion chambers after head gasket change

Check the exhaust cover gaskets.
 

lotsofish

Cadet
Joined
May 25, 2009
Messages
19
Re: 78 Johnson 35hp - water in combustion chambers after head gasket change

I didn't think of that but it makes sense. The problem with these old motors is that you know taking them apart is going to ruin the gaskets and replacements all have to be ordered. Iboat doesn't have the exhaust gaskets for my motor either. Could I use rtv red for the exhaust if I had to?

I dont know this seems like a new problem. I cant say for sure no water was getting in before but it wasn't idling rough like it does now. When it died because of the head gasket, it was running good, then it slowly lost power and wouldn't start.
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: 78 Johnson 35hp - water in combustion chambers after head gasket change

You will need the proper gasket on the exhaust cover.
 

lotsofish

Cadet
Joined
May 25, 2009
Messages
19
Re: 78 Johnson 35hp - water in combustion chambers after head gasket change

I think I found the problem. I didn't notice it before, but today I found there are a couple small pinhole leaks on the top of the crankcase letting water leak outside the engine.

So a cracked crankcase, is there any hope to repair it, or should I just part the thing out? The holes are so small it's impossible to see them unless it's running. JB Weld might work for the outside leaks, but I don't know about the ones on the inside letting water into the cylinders.
 
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