Flutter below 2k rpm

Not making excuses, but the fact that we have become accustomed to fuel injected cars. You can forget what it feels like to drive a carbureted car. That being said the AVS 2 is supposed to smooth out the transition compared to the original AVS. So the flutter happens at a steady throttle position at 2000 rpm? Might just be were the carb is transitioning off the idle circuits to getting fuel through the boosters. If it is happening as your roll into the throttle you could play with the accelerator pump lever position. Closest hole to the carb is the biggest/ longest shot.