What Viper is telling you is pick a direction to turn, turn 1/4 revolution in that direction, wait 30 seconds to see if it has any effect, do it again in the same direction and wait to see if there is any change, go no farther than four 1/4 turns if no change! Reset the screw to where it was when you started the adjustment, then go 1/4 turn in the opposite direction, wait to see if there is any change. You SHOULD see some change in this direction if there was no change in the first direction. When the RPM starts to increase, like Viper said, STOP ADJUSTING!