Looked around the site to find an answer but no.... I've read and heard that the screw has to be out 4.5 turns. While fiddling around with it (trying to get the motor running smoother) I noticed that the only effect it has is increased revs from out 1 turn to fully shut (all the way in). It's a new engine. What effect does this screw have and why would it only work out to 1 turn? Should I adjust it within that 1 turn range?