ORIGINAL: kruzin55
I had the exact symptoms last fall. One weekend the engine ran great and then the next all I could do was get it to start and then it would die on transition. I adjusted the needles multiple times and asked everyone I knew. It had spark and gas. I was about to change the carb, when I noticed a small crack in the yellow poly tube that is connected to the carb. Not the fuel line, but the three inch line that provides vacuum to the internal gas pump. Replaced it with yellow gas tygon and she started right up. Who knows how I had damaged the line, but the crack was very difficult to see. Hope this helps.
I think that may have done it! The vacuum line was old a brittle, and appeared to have a small crack in it. I put a piece of tygon on it, and it ran longer than it did a couple days ago. I couldn't run it too long due to noise issues at my house, but I'll get it out the field in a day or so and hopefully get it tuned in and go flying. I'll make sure to report back when I do.
Thanks for everyone's help, Brett