[stouchton]

Have had this issue, and solved it - a couple times cause I keep tinkering.....

Some of this is mentioned above - I'm just rehashing what I have successfully done.

Make sure timing is correct, and make sure dwell angle is correct (point gap at .020"). Stay to the wide side of point gap, not narrow side - it effects your idle. Err on the wider side.

Make sure float level is correct.

Run engine up to temp, open GAV 1/4 turn. Advance and idle levers all the way up.

Adjust idle to slowest obtainable speed. If idle mixture is all screwed up, then start with idle mixture screw 1 1/2 turns out.

Adjust idle mix screw for best idle. Readjust idle speed to lowest obtainable, then readjust idle mix screw.

Rinse and repeat a few times. If you have a broad range (1/2T to 1T) where the idle mix seems good, set for in the middle.

When you are happy with idle mix, turn mix screw in 1/8 to 1/4T.... 1/4T might be too much. This makes the idle mix slightly on the rich side.

Now take advance lever 1/2 to 3/4 of the way down (normal running position). Advance idle speed to a comfortable idle. I set mine based on generator - spin fast enough to be at 0 amps or slight charge at idle with all lights and stuff off - just ignition drawing juice.

Now, play with GAV. Close it and wait. Open 1 turn and wait. It should have no impact to only a slight impact (slightly roughen idle). If it has too much effect, lower idle speed slightly. Mine has only a slight impact. If I lower the idle speed slightly it has no impact but my generator loses ground at idle (discharging slightly).

Put GAV back to 1/4 open.

Road test. This has always cured mine from stalling when stopping.

It has also cured mine from backfiring while coasting. For me the 2 issues seem to go hand in hand.