Anyone have any suggestions for the following tuning issue I'm having with a nova +4:

After clearing the carb with a full throttle pull, engine comes down to idle. 1 second later it goes to a higher overly idle for 2 seconds, than back down to a normal idle for 20 to 30 seconds.

When I richen the LSN from this point, it goes to a high idle and then to a rich low idle after about 6 or so seconds and dies sooner.