Yeah it sounds like the main jet seal that goes under the brass washer where the main jet screws in.. You'd have to screw your needle all the way out, and make sure that the nut it screws into is all clean, then that rubber seal, brass washer, keeper spring.. then the needle screws in through all of that.... The rubber pinches down on your screw between the washer and jet and needle and seals it all off....
If your float bowl has the drain underneath, that has a spring on it....it goes on that assembly, inside the bowl. If you don't have the drain on the bowl, you don't need it. Also, a lot of guys think that their jet is leaking when it's really coming from above and leaking down. Did you put the seat in correctly? Groove side in first. Scott.
