If you have removed the lock nut carb(gs70357-05)totally then you must just with a bit of pull and wiggle it will come undone.They are fairly tight in the housing but you will be able to do so,ask someone to hold the engine while you pull.The o-ring is at the top so don't worry about ripping it.

Why do you want to take off if i may ask?

If you reinstall the carb,use a bit of afterrun oil on the carb housing and it will go in easy.