[TinCup]

Great write up here. Tom's articles are always on point and early on I relied on them when starting on carbs. Sounds like you are on target and their have been some good suggestions already posted. I will just add that I too like the Viton tipped float valves that have been changed to work with alcohol gas. One thing I have found from time to time is that if the vent on the gas cap is plugged the tank will pressure up and force gas through the main cutoff valve which almost always leak some. Do they all leak? No but a great many do due to faulty setup and parts. Keep at it and let us know the conclusion.