Recommend a good semi-permanent rtv

[guy48065]

All the sealants at my local auto parts stores are "ultimate_strength, everything-proof, high-temp" products.
What should I be using on lower units, case halves, plastic intakes, etc that are supposed to be somewhat less than welded permanently together?

 

[Scott Danforth]

Permatex #3 (aviation)

 

[guy48065]

Is that paste better than a silicone sealer?
I've never seen permatex recommended for this.

 

[Scott Danforth]

its in the VP manual under their version of it. OMC uses their version on the Johnnyrudes. and Merc has their version of it.

 

[Lou C]

RTV like what you use on the China Wall area of a Chevy small block, one of the best I have found is the Mopar Auto trans fluid RTV. It is a little expensive but seals well. But normally you could use Ultra Black or Ultra Grey RTV.
Some have used The Right Stuff on things like differential covers etc.
Permatex Aviation or the OMC version (Evinrude gasket sealer) I think of as more of a sealer for gaskets and also to seal bolt threads to keep water out.

 

[dingbat]

One size doesn't fit all......
I would not install any "plastic intakes" parts using silicon RTV. You should use a Polyurethane sealants like 3M 4200 made specifically for the such applications.

Nothing on my boat requires an RTV sealer so I'm not help there, but.....I do know that the sealant recommended by OMC back in the day for the Service (water pump gaskets and screws) is 3M, Nitrile High Performance Rubber and Gasket Adhesive #847.

 

[guy48065]

Thanks guys.
Some surprising info here.
Really didn't think Permatex would hold up under water but I might give it a try. Much as I hate the stuff I have to admit it's the one sealant in my drawer that never dries out after opening. I've thrown away SO much more silicone than I've ever applied.