Am I sporting a vac leak?

[AK260]

Brilliant!!!! [emoji1787][emoji13][emoji106]

[AK260]

Hey Captain, is this the one? Only £8 on fleebay, shall I hit buy?

 

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F163516321436

 

 

And then there is the SUPER grey, so which is best!?

 

 

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F184243311437

[Captain Obvious]

Neither of those are what I recommend for gasoline intensive applications. Both of those are the grey RTV silicone that I used to use everywhere before I discovered the MotoSeal. (The Ultra Grey is what they cell it here. And from what I can tell, the "Supra" (not Super) is what they call it elsewhere on the globe but it's the same RTV.)

I took a look at ebay UK and found the stuff, but I didn't find anything IN the UK. It's all shipped from the US or Lithuania. I'm guessing they don't sell it in the UK.

Here's a pic from your ebay of the MotoSeal:

And another pic of the same stuff in a different package:

 

[Captain Obvious]

The trick is that the Motoseal is not an RTV (like the Ultra or Supra Grey stuff). Instead, it is a solvent evaporation cure based sealant and not a silicone.

Once the solvent evaporates, the rubbery solids remains are not particularly soluble in gasoline. According to the MSDS, it mostly uses the following:

XYLENE
2-BUTOXYETHANOL
ETHYL BENZENE

If you can't find that brand name, there's got to be something within your shores that is similar. Finding it is the trick though.

[Zed Head]

Here's a popular one.  I read about it for use with transmissions.  You can disassemble easily if you make a mistake, so I got some.  It ends up as a very thick goo after it dries.

The solvent, or carrier fluid, smells like ethanol (in the Hylomar Blue).  Says fuel resistant.

http://hylomar.com/hylomar-product-range/gasket-jointing-compounds/

Edited May 11, 2020 by Zed Head

[AK260]

Thanks CO - I totally misread your original post! Thanks for the correction. [emoji106][emoji106]

[Captain Obvious]

Glad to help. To summarize the sealant the sealant stuff... I've never seen a silicone RTV sealant that said it was recommended to be used in a gasoline environment. All of the ones I've looked at say "not for head gaskets or for contact with gasoline". And while the RTV stuff won't instantly dissolve or burn down, fall over, and sink into the swamp... You can do better.

I tried that Motoseal stuff because the package actually said "Gasoline resistant" on it and I've been satisfied in those applications. I'm sure there are other options.

All that said... I would NOT use the Motoseal between your carb domes and the bodies. I'd be worried that it would work TOO well and you wouldn't be able to get the domes back off easily. For that application, you want something that doesn't work "as well".