Flooding AVS2 - What am I missing?

Quite a few years ago I had pretty much the same problem. 1 of the seats wasn’t tight in the air horn. Loose by about a thread or so. Fuel was getting past the threads and making it flood. Tightened the seat then no more flooding. Yet it sealed when inverted. Also seen that if the needle has a ring around it where it seats that it is unable to seal. Yet when u try to blow thru it u can’t Kim