I'm new to the hobby and I need a little help doing an engine swap. How do I get the nut off the flywheel? Do I need a special tool? Is there anything else i should know? Thanks

Hold the fly wheel with a set of channel locks or a fly wheel wrench that you buy at your local hobby store. Undo the fly whell nut with a 5/16" wrench or socket or nut driver (depending how tight it is). Once you have removed the fly wheel nut, tap (and I do mean tap) the fly wheel off the collet with a hammer by placing the output shaft (either threaded or SG) on a hard surface.