Is this the high speed needle? If so, isn't there a detent "spring" that applies pressure to the detents on the main needle valve screw head? (the knurled part that you turn with your fingers.. that metal thing that presses against it).

If you do have one of those, and you should, you can carefully bend it so that it makes good contact with the detents or knurles on the finger-twisting part of the HS needle valve.

CGr.