fuel scre adjusting itself?!

[LoneWolf]

Hi all, got a bit of a weird problem, my fuel screw on my mk2 AAZ conversion seems to keep winding itself out and leaning out my mixture 

 its got the locking nut on it, and i keep tightening it down and have even loc-tited it to the screw, but it keeps doing the same thing!

 has anyone come across this before, and if so, how did you sort it??


 Matt