35HP – Exhaust cover gasket question

[nj-boatbuilder57]

35HP Exhaust cover – do the two gaskets go on "dry" or is some sort of sealer required? If something is required, what do you all recommend?

And what determines if the inner cover is no good? Just holes / burn throughs?

[Bob Wight]

You should use a gasket sealer for the exhaust cover gaskets. I use either BRP Gasket Seal Compound or Permatex Aviation Gasket Sealer #3. Yes, look for pinholes, burn-throughs or pitting on the inner plate. Might also lay the plate on a known flat surface and check for warpage.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[dan-in-tn]

OMC/BRP Gasket Sealing Compound, Mercury Perfect Seal, or NAPA Aviation Cement (Permatex) is all the same stuff & exceptable on any gaskets in any situation. Even head gaskets that say no sealer required or use no sealer! If you have ever taken apart (late model) factory motors you would know the factory uses sealers on the gaskets so they past the pressure test before the motors are run.
The guys in salt water practically bath the screws in the stuff so you have a chance to get them out later. It is a good anti corrosion protector. It is not easy to paint over & probably the reason the factory stopped using it. That & cost saving.
As far as the baffle, you are looking for any pits, sign of corrosion, or burnt spots. If in doubt or warped best to change it out?
JMHO.

Dan in TN

[nj-boatbuilder57]

Thanks guys!

[nj-boatbuilder57]

OK….so I removed the cover. As you might expect the exhaust-side was filthy & had a lot of carbon buildup, but there was no sign of water on the exhaust side or vice-versa. Naphtha + a brass brush, followed by some naphtha-wet 400 grit, and the dish is clean.

So the question becomes "how much pitting is too much pitting?" Nothing is burned through, but the deepest corner seems pretty deep.

Thoughts?

I can get a NOS plate on eBay for $30…seems like a small price to pay for "insurance", but if you think this pitting isn’t too bad, maybe I’ll just re-use it.

What’s the verdict?

[Bob Wight]

I had some similar pitting on one of my motors and I just applied some JB Weld to it and sanded it smooth. Seems to work just fine.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[nj-boatbuilder57]

can JB handle the heat of being that close to the raw exhaust? It’s only good to 550F when cured.

The "JB extreme heat" looks to be more of a caulk (it’s not a 2-part product), so I’m not interested in it….

[Bob Wight]

Sorry, neglected to note that I used the JB Weld Extreme Heat product. It’s good to 2400F and although not a 2-part mix I found it work fine for me. Just need to allow it to get to full cure before putting it into use.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[garry-in-michigan]

Clean it off with vinegar followed with alcohol the get down to solid base metal and you will be fine with the hi temp JB Weld. . . 😎

[frankr]

I’d replace it. Unless you want to tear it down again next summer to see how it’s doing. Besides, once it perforates, game is over before you even know it.

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