Gear case lapping question

[Mumbles]

Don’t trash that gearcase yet!

I’m betting if you use a sealer such as Permatex Ultra Black, which is an RTV Gasket Maker, it will seal up just fine. It’s designed to fill gaps and is also an adhesive. When applied to a clean surface, it will stick like a fly on a screen door! Let it set up overnight before adding the oil and your problem should be solved!

[johnny-infl]

I am into the final stretch of getting my gear cases back together and noticed a potential problem.
The seal groove is about 1/8" wide and the Spaghetti Rubber Seal is much less in diameter…….
I ordered two gear case seal kits from two different vendors and both are the same size.
The photos I see (such as Figure 6-18) the rubber seal is the same size as the groove in the case.
Any thoughts on this ? And yes, I have gently lapped all mating surfaces and they are dead flat
and also have some Scotch-Weld 847 sealer.

This is the same issue for a ’66 33hp and ’60 40hp Johnson.

.

[Mumbles]

You need the extra room to allow the seal to squish. The seal itself stands a bit proud of the case and it has to go somewhere when everything gets tightened down.

[johnny-infl]

yes, I understand the concept, but, there is enough room left over for another seal.
I guess I am letting my mind drift back to working on our Navy Nuclear Submarines
where the seals had to be pressure tested to 3,000 feet. LOL – not just a piddly 5psi.
Will use them as they are and fill the void with sealant.

Thanks for the timely response !!

.

[jeff-register]

I’m with Pappy!
In 1979 My second motor ever was a 1953 Evinrude 15hp. When I bought it the impeller needed replaced. I couldn’t leave well enough alone & got inside the gearcase. Everything was clean enough to eat off of it. I replaced the shift O-ring was all. Not knowing much about marine mechanics I used a tube of electrical silicone & reused the seals. I let it dry in my hot garage for a week. I live in the desert where it was 125 degrees inside the garage. After it cured & then some I filled it with gear oil. It never leaked or took on water for the 3 years I owned it.
Yes, I have improved but a good cleaning & sealing fixed it up. It has cross hatched pattern on the mating surfaces which is there for a reason & better to be left as the factory machined it.

[bill-mcnamara]

Is your skeg section from a different motor possibly?
Difficult to seal up "blended" units.

[johnny-infl]

There is very little seal material "standing proud" of the groove, this is what
concerns me. They have not been lapped down past the factory cross hatch finish.
I am going to NAPA today for some other stuff and will see if
they have spaghetti seal just a bit bigger diameter that is oil/fuel resistant.
But, like Mumbles said, the excess material needs a place to go when it is mooshed down.
and, as Pappy said, sometimes use the existing material….. so I will try to find what
came out of the foot first and see if it is salvageable. (I tossed it in a corner somewhere).

[Mumbles]

If you can’t find spaghetti seal in bulk, A large 3/32" thick O ring from an industrial supplier will work to.

[johnny-infl]

Dropped by the NAPA store and there was an old OMC Johnson enthusiast
at the counter and he recognized my part right away and we got to talking.
He said the modern spaghetti seals "will work" as designed and not to worry.
so – problem solved. Onwards n Upwards !!!
Oh, I found the old seals and they "appear" to be the same small skinny size as the new ones.

He also said that a lot of people are using the PERMATEX 811282 GEAR OIL RTV GASKET MAKER
in boats these days . . . . can anyone endorse or not endorse this product ?

THANKS everybody !!

.

[jerry-ahrens]

Don’t worry about the small size of the spaghetti seal, that’s the way they are. I would highly recommend the 847 sealer in this assembly. It works excellent. You will have plenty left over for other jobs down the road, so it goes a long way.

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