What tool are you using to try to get the flywheel off? It's been my experience that a dedicated flywheel puller is pretty necessary in removing the flywheel. Some folks have had success using other means, such as a harmonic balancer puller, but a good quality small engine flywheel puller may be required.
Welcome to the forum!
2017 SKS 800, 2007 Dragon RMK 700 155", 2008 RMK 600 155", 95 Prowler 550 2-up, Really OLD AC Cheetah