I would have to seconded that also about McMaster.  They are about 45 minutes from here and I have ordered in the AM and had the order on my door step that evening.    I too use the viton in the tank with the brass tube.  I had to learned the hard way a few times how to run a fuel system.  And, I am glad to here that you are getting good results with it.   My motor is on its way to Todd.  I fractured my main shaft.  Don't ask.  Just more of that hard way of learning.