I thought there was an adapter fitting that threaded into the carb first? Then the fuel line to the adapter?
If it was originally 1/8 pipe and the P.O. Tapped it out to 1/2 straight you may have a hard time sealing that with anything.
From your description it also sounds like its also cross threaded
If the locktite doesn't work you may have to repair the inlet.
...example... I made the mistake once of using pipe dope in that area. It caused a flooding problem for me. If just one little spec get loose it can cause problems at the needle and seat.
Good luck
