Good to hear it's running. I have a process I use to set both needles and when it is completed I have found these engines to be superb. About the low speed, it is really effective when the throtttle opening or throttle position is nearly closed. This could be a range of rpm due to other factors and if it is rich or lean then the effects carry over into high speed until that needles' settings take over. That may be a moment or two. When these engines are tuned well and running they have no equal. Got to go to the field now, drop a line if I can help w/ anything.