they make a new threaded fuel inlet nut thats desigened to fix this problem.
this happens alot the new inlet nut will have slots cut in the end of it where the threads start. kind of a thread repair set-up with longer threads.
should be able to find one at the auto parts store. like napa. not auto zone..
if u can't find one p.m. me and i will look at my stash i might have one
your pal mark
