I just bought a ZipTy fuel screw. I removed the stock screw and made sure that the sping, washer and o-ring all came out with it. The problem is when I screwed the ZipTy in it only turns in 2 to 2-1/2 turns from fully out. The instruction say it should be 8-11 and then back out 1-1/2 turns. What might be keeping it from seating? I'm ok with pulling the carb but if there is something easy I should be looking at then I'm all for it.