I tried the viton tipped float valve in my NH carb about 4 years ago. Worked fine until this season when it started leaking. The bowl was always wet, due to too much gas flowing in. Just pulled it and replaced it with an original type brass valve and seat, reset the float height, and no more leaks. Anyone else have longevity issues with the viton valve?
I haven't experienced it, but I've heard of it. It seems reasonable that synthetic rubber, like plastic or real rubber, would deteriorate with age.
I had one with the viton tip. It had taken a set and was no longer pliable. It would not seal. Replaced it with a good use steel needle and got rid of that problem.