As Buck has stated, you must be lifting the flywheel. Don’t be afraid to really smack it. Heating the flywheel around the crankshaft to expand it may help. Also, taking a piece of wood and placing it off to the edge of the flywheel and striking down with a hammer, while holding the flywheel up, can also be helpful. Go all around the edge of flywheel and try hitting the bolt again.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.