thanks for all the input. I have read about the unscrewing the nut to begin. In a TR4A book, and an SU Carburator manual I read two different numbers. One said to unscrew it two rotations (12 flats) and the other was two and half flats (15 flats). I have not tried the 9 flats, but probably got close. I will try again this weekend with the 9 flats.
That colourtune setup looks like it could assist in fine tuning.
Best regards
