I think screwing in, clockwise makes the mixture weaker , that`s what the garage did when I had the emission tested to bring it down,and sending th results to the DVLA trying to get them to reduce the road tax,but no luuck as my BUG is 1991 model and outside their year.
screw it all the way home, back it out 2 1/2 turns, start engine and run until operating temp, screw mixture in slowly until the engine hunts (to lean) then back it out slowly it will smooth out then start to hunt again (to rich) screw back in slowly and you will hear the engine start to run smooth when it does stop there, or if your a novice i'd recommend gunsons colour tune, basically a spark plug with a window, you would be aiming for a nice blue flame.
Thanks for the replies. Very useful. Time to get twiddling