For one thing, you didn't say you replaced the spark plug.
When you put the new carb on, what jet did it have in it? Was it the same number as your old carb?
Take the head off and check the cyl and make sure to use a new gasket cyl. to block.
Also make sure the intake gasket is good.
Check oil injection if you're using it instead of pre-mixing.
Not likely but clogged muffler can stop acceleration.