Your 570 probably just needs some tuning. You're going to have to learn how to do it because there is no such thing as a ready to run carburetor and the same thing (or some totally different problem) may happen with another carburetor. The manual for the 570 goes over some initial tuning. Do that if you have not already. A book titled How to Super Tune and Modify Holley Carburetors is a good read, to help you understand what you are doing. While it is focused on Holley Style carbs, the info applies to all so long as you understand the differences in functionality between carbs.
Add an oxygen sensor. Install it temporarily, if you don't want it to be a permanent fixture. This makes tuning a lot easier and helps to better understand what is happening.
Lawrenceville, GA