Topic: Firestone Crankcase sealer – Antique Outboard Motor Club,Inc

This topic has 17 replies, 8 voices, and was last updated 9 years, 6 months ago by Mumbles.

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May 10, 2015 at 3:27 am #1453
Buccaneer
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US Member
Getting ready to button up the crankcase on my 1950 Firestone 5hp
soon, and realized that there’s no gasket between the crankcase
halves, therefore I need sealer.
Scott manual refers to Permatex 3 and Aviation Grade Permatex,
but I think they’re the same thing.
I see there still is a Permates 3 produced. (add below)
Small container is about $8 bucks.
Would the product below be okay, or should I look for
an OMC product?
Thanks, Buccaneer

Permatex 80017 Aviation Form-A-Gasket No. 3 Sealant
Slow-drying, non-hardening brush-top sealant
Resists gasoline, oil and grease
Approved for use in aviation as well as automotive applications
Suggested Applications: Close-fitting machined surfaces, sealing hoses, solid gaskets
Temperature range of -65F to 400F

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May 10, 2015 at 4:37 am #15649
legendre
Participant
That should be just fine, as should a material like Yamabond 4 (and its Three-Bond equivalent) or the Permatex Ultra Grey. The Yamaha / Three-Bond is the same type of sealant used by all of the Japanese motorcycle manufacturers to seal gasket-less engine cases. The Ultra Grey is an RTV material that’s spec’d by many current auto manufactures for similar applications, though it’s also used along with gaskets (such as on a valve cover).

My experience with the Permatex Aviation sealant, is that it tends to be a little on the thin side, and also sets up a bit more firm than the description might suggest. That is, it behaves more like a glue than I’d like.. but it should still be OK for anything you don’t plan to pull apart anytime soon.

(Your experience may vary)
May 10, 2015 at 12:48 pm #15654
Buccaneer
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US Member
Thanks Legendre for you thoughts and time!

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May 10, 2015 at 1:39 pm #15659
The Boat House
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- This reply was modified 6 years ago by The Boat House.
- This reply was modified 3 years, 9 months ago by The Boat House.
May 10, 2015 at 1:42 pm #15660
49hiawatha
Participant
So Tubs what is your backup stuff for fuel line fitting??
May 10, 2015 at 1:50 pm #15662
The Boat House
Participant
I dug it out of the trash to be
sure and the part number is 80019
and doesn’t have a No.3 on what I have.
I need to try what you have found.
49Hiawatha I’m sending you a PM.
May 10, 2015 at 2:39 pm #15665
chris-p
Participant
quote 49Hiawatha:

So Tubs what is your backup stuff for fuel line fitting??

I use Blue Loc Tite after taking Franks advice years ago.
May 11, 2015 at 12:37 am #15686
Buccaneer
Participant
US Member
It looks like the only difference between the Permatex Aviation sealant 80017
and 80019 is the size of the tube / container.
I did find this spec for it that has me wondering if I want to use it…

"Chemical / Solvent Resistance – This product retains effective properties
in contact with water, ethylene glycol, non-ethanol containing gasoline…."

So far I’m still able to buy non-oxygenated gasoline, but who knows in the
future.
Is the OMC sealer ethanol proof?
Thanks, Bucc

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May 11, 2015 at 1:12 am #15690
legendre
Participant
quote Buccaneer:

Is the OMC sealer ethanol proof?
Thanks, Bucc

I can’t answer that question, but the Yamabond 4 / Three-Bond and Permatex Ultra Grey products don’t seem to care one bit about any solvents, oils or fuels, so far as I’ve ever known.

And FYI, I use yellow Teflon plumber’s tape to seal fussy copper & brass flare nut connections. At first, I add a couple turns to the threads.. and if that doesn’t seal it (it does, 90% of the time) then I add a single layer to the seating surface itself. Never had it fail, but as ever, YMMV.
May 11, 2015 at 12:55 pm #15707
The Boat House
Participant
- This reply was modified 6 years ago by The Boat House.
- This reply was modified 3 years, 9 months ago by The Boat House.
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