Check idle mixture screw adjustment. Sounds like it could be starving for fuel when your foot is not on the gas pedal. I had that going on and about 1/8-1/4 turn out on the idle mixture screws solved it.
If that isn’t the symptom and doesn’t fix it your carb is out of adjustment somewhere else or another issue is going on.
i have played with idle mixture i dont seem to help but i will take it out today and when it tries to stall out all give the screw a turn and see if it make a difference thanks