Bill, I also have no detectable difference in adjustment at idle.

I also have a hard time understanding what changing my bolt to a different bolt would do.

I do notice however, that if I adjust the bolt with the idle up slightly, using the stop lever, I can increase or subside a surging quality in the idle.

Aaron, I think, just explained why my engine idle will dip and become slightly irregular when I let off of the gas while driving and I coast. It was strange at first, to have my engine so quiet, I had to turn off the radio, and air to see if It was still running!

My question now, is what would happen if the bolt were too far out?