Keyster o rings

Are the o rings in new Keyster kits resistant to ethanol?  I bought them for the gaskets and float valves but I'm curious about the o rings.

Yes, they are resistant to ethanol.

What specific O-rings?  I've bought kits before, that had O-rings in it, but the O-rings didn't fit, or at least some of them don't.  

Ed, the kits should arrive in a day or so. They are keyster kits for 1978 VM26 carbs.  I'll check the o rings for fit, may have to order some from you.  At least I'll have the gaskets and float valves. Existing brass will be cleaned and re installed.

The kits came today from retro-motorcycles and they are NOT Keyster parts. Sudco packages with Napco parts in them.  Returning them with negative feedback.

I buy these, for the float valves and gaskets.  Comes with a 15 pilot jet, which is reasonable quality.  Only $11.99 each.

www.siriusconinc.com/products/detail/562

Thanks Ed.  That's what I expected to get and a better price.

If you dont know the compatibility of most rubber materials and a specific chemical you can usually put the rubber in the chemical overnight. If it gains more than about 10% in weight, its not compatible.

Common misperception with fuel system o-rings, is that some people think they should be unaffected by gasoline.  Reality is that gasoline will cause them to swell slightly, and that's part of what makes them seal well.

On my old car, after removing the fuel pump, the O-ring had swelled up and wouldn't fit back on the tank.  I didn't have time to replace it, so I put it in the oven at 170F for a while, and all the gas was driven off, and it shrunk back to size.  

Bottom line, for common carburetor O-rings, Nitrile/Buna-N works well.  No need to chase Viton or the like.  Once in place, captured in a space between parts, after gasoline hits it, the rubber will swell slightly, creating a reliable and lasting seal.