The flywheel is a close fit on the crankshaft flange, not quite a press, but it sometimes takes a little persuasion to get it off. Try a couple of pry bars, one on each side of the flywheel, and rock it off a little at a time. Be sure to have someone there to catch it as it falls, as it might release suddenly- - - -and just where were your toes? That flywheel is heavy, and the starter ring gear makes funny-looking marks in a concrete floor. Don't ask me how I know that!
Jerry