Farmall A needle valves

(quoted from post at 22:17:46 12/14/13) Will a Cub needle valve work in a Zenith carb for an A? I have been having lots of trouble with sticking viton tipped needle valves and found a place that has some metal tipped ones. I didn't use to have trouble with viton tipped valves until E10 came to my area, now they only last 6 months before they stick badly. The tips just turn really into goo.

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(quoted from post at 11:19:58 12/15/13) I agree with Rusty, there must be something else going on (It could be an additive your fuel supplier is using (doubtful), or it could be a cleaner you might put in the fuel. But Generally there has been no history of Viton being degraded.
Metal tips are no problem, so if you find a source, share it with us. Many on here prefer the metal tip. Always shut off the tank valve as a policy. Have good luck with it. Jim

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(quoted from post at 14:55:50 12/15/13) I do not add anything to my gas, and I have tried
different brands and they all turn my neeedle
valve tips to goo in 6 months. I can take the carb
apart and see even the weight of the floats isn't
opening the needle valve, I have to shake it
really hard to before the valve drops open.

There are many different grades of viton, and only
high grade viton lasts with E10. I am also into
old cars and a quick look on old car forums you
will see there is alot of talk about E10 eating
away cheap grade carb rebuild kits from the chain
stores. There have even been tests of different
grade viton needle valves submerged in E10 and
E85. So of the cheaper ones turned to goo in 2
hours while the better ones remained okay after
weeks. My old Buick has a viton needle valve that
doesn't give me any issue but it is a known high
grade viton valve.

I have even searched on tractor forums and
sticking needle valves seem to have become alot
more common in recent years with tractors. It
seems while you can get high grade viton needle
valves for some car carburetors like Quadrajets,
it seems no one makes high grade viton valves for
old tractors.

I have tried different brands of replacement
needle valves and they all have failed in 6 months
on me. Maybe they are adding something else into
my gas that you guys don't get? Maybe you have
lucked out and have higher grade viton needle
valves than what I can find? All I know for sure
is I am tired of changing out needle valves and I
want to try an old style metal tipped one. The
only one I can find are for Cubs. However some of
the parts sites show Needle valves between Cubs
and As interchange, is this true? Sorry for the
long rant LOL, but this has problem has been
really getting at me.

Due to the advent of EFI, carburetor parts are
slow sellers these days and it is unlikely anyone
will step up with high grade viton needle valves
for our old iron. In which case I am forced to
downgrade to metal tipped valves that can
witthstand E10 better if I can even do that.

Just a quick side note. You will see some folks
post that they have not had any troubles with this
new fuel, even so, most of this comes from the
fact that their old rubber parts are near the end
of their life cycle. New rubber and low grade
viton is very soft, and in contact with this new
fuel fails immediately. Rubber and low grade viton
that's been in service for a while before being
exposed to E10 is much harder, and resists
swelling in contact with the new fuel. Eventually,
however, it will still crack/break/stick.

The best quality Viton seal is impervious to the
new fuels. They will be very dark blue, cheap
viton will be lighter blue, and all the different
brads of needle valves I tried on my A are all
very light blues. Anyone run into a brand that is
a darker blue viton?

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