Johnson 35 - Water in #2 /Bottom Cylinder - Head Gasket and Exhaust Gasket Questions

[Gordon02]

Hi Guys, I've got a question that some of you who've been inside one of these outboards will be able to answer. I bought this 1979 Johnson several months ago and was told it ran perfectly when removed. Well, 4 months later (been restoring the boat), the outboard does start/run but in my driveway test, I was getting a miss. The sparkplugs revealed the bottom plug was way too clean, the piston top is also clean - all from the ingestion of water. I immediately pulled the cylinder head cover and cylinder head to check for obvious signs of heat or freeze damage and/or a broken gasket. The cylinder walls look good and the exhaust ports off to the left side look identical top and bottom leading me to believe the problem is not exhaust cover related.

Here is my question - When I look at on-line fiche and at the factory's shop manual, the exhaust cover looks to be "common to both cylinders" - I mean that these look to share an open space that both cylinders would have water - not just the #2/bottom one. Now the reason I have asked is that I tried to remove the exhaust cover, but clearly there are multiple exhaust cover bolts that will break. I stopped short of twisting these off and force the powerhead removal - something I plan to do over the winter of 2015/2016 when I'll do a complete overhaul of the engine and paint. For now, I want to fix the leak and go fishing. If I'm right about the exhaust cover, then I'm simply going to clean the surfaces and install new head and cover gaskets.

Inputs will be appreciated. Thanks, Gordon

 

[F_R]

Your assumptions make sense, but are wrong. Yes, it is a common chamber, the more than likely the exhaust baffle plate has a small hole in it, which is squirting water in a stream---aimed at the bottom ports. Not only that, there is gravity in there, making the water more apt to go to the bottom.

You have determined the leak was not the head gasket, right?

You must fix this problem before the water causes rusting of the bearings in the crankcase. And yes, the water does get into the crankcase.

 

[Gordon02]

I don't know if the head gasket will solve the problem yet or not. I wanted to get input on the exhaust cover. I'd love to pull it - but I am 100% sure that I'll break at least some of the cover's bolts. They are frozen and rusted so I was hoping that you would tell me "yes both would have traces of water" - you didn't.

Now, with the acceptance that I have to pull the powerhead and remove/replace the exhaust cover - how can those bolts be coached out of the block without breaking? They don't move and the engine's paint is sealing any/all gaps that penatrant like Kroil or Blaster will need.

As for the head gasket, here are some pics. I don't see a clear sign of water tracks, in fact, the #1 cylinder has a blown sealing ring explaining why the compression was low on that one.

Again, thanks for all inputs.

 

[F_R]

Well,, it certainly was blown and probably leaking. I guess it is up to you to see if you want to try it first. Not much to lose except time and temper.

Trust me, those exhaust cover screws can be a challenge even for the pro's. I have removed literally 1000's of them and still break some. Heat---hot heat like an acetylene torch is a marine mechanics best friend. But you probably don't have one, so it is going to be difficult at best. Drilling them out after breaking them is even more of a challenge. A learned skill from much practice, for sure. I wish I could be more encouraging.

 

[Gordon02]

No Title

I wanted to come back and post the results - Head Gasket solved the problem. No water, no miss, and running perfect! I never tried to get that exhaust cover off - those bolts are going to snap and I don't want to deal with those right now. This winter, I'm going all the way to the crankshaft. I'll deal with bad and broken bolts then. Thanks again for the inputs. Gordon

 

[jasper60103]

I wanted to come back and post the results - Head Gasket solved the problem. No water, no miss, and running perfect! I never tried to get that exhaust cover off - those bolts are going to snap and I don't want to deal with those right now. This winter, I'm going all the way to the crankshaft. I'll deal with bad and broken bolts then. Thanks again for the inputs. Gordon

Good job and thanks for the update. It always amazes me the previous owner leave out these little details.
That head gasket didn't blow just by sitting too long. :lol: