If I remember correctly it goes back to full advance when under 400 rpm or something like that. I am not sure of the exact # now. A speed way lower than the engine is capable of idling at. But still a rpm speed lower than you are flipping it over when starting it. So under 400 rpm, full advance. Over 400(starting to idle and up) it is retarded untill it reaches it's pre programmed advance curve. It's determined by the speed at which the magnet passes by. Something like that as I remember it anyway.