I usually back the bolt out a little bit then tap on it to dislodge the one of the cinch pieces from the carb. Once you do that, you can usually wiggle/twist the carb back and forth and it will break free from the other cinch piece.
Some are multi-piece, others are a single piece.
This is a one piece, when the nut tightens, the curved part bites into the side of the carb to keep it locked in:
With that, you loosen the nut a bit, then tap on it to force it into the engine and dislodge it from the side of the carb neck.
This is a multi-piece:
The part on the bolt head side isn't threaded and as the bolt is tightened, the other side that is threaded is pulled towards the carb and the side on the bolt head side slides into the other side of the carb, so it's locked in by both sides vs just one like the 1 piece up above. For this kind, backing the bolt out a few turns, then tapping on the head of the bolt dislodges the opposing side, then you wiggle the carb to get it to dislodge the other side.
With all the engines I've ever owned, I've never seen one with o-rings on it like that multi-piece one I posted here. I'd usually take them out, clean the oil/fuel off it and out of the hole, then put RTV in it when installing the pieces to ensure an air tight seal. Guess I just never had a "good" engine. lol!