Originally Posted by stefan

if your engine is idling high after the straights, you bottom end is too rich.

Here's why: When you LSN is too rich, you have to compensate by turning in your idle set screw. Now, when you run the engine in the infield it is loading up but when you go down the straight it's clearing out. So when you lift the throttle, your idle speed is too high and it takes a bit to load it back up again and the idle speed comes back down.

if your engine was too lean, it wouldn't idle down but keep "singing".

Try to close the LSN about a 1/8th and then re-adjust your idle screw.

Make sure that you make all adjustments after at least 5 hot laps on the track. Due to the insulated carb, it takes a bit to bring everything up to operating temps.