This manual may be of some help. As a service tech I’ve used the following method multiple times with success, but you must be very careful when doing it. Remove the fan and reinstall the flywheel bolt until you have a gap of 1/16”-1/8” between the flywheel and bolt. Take the largest screwdriver you have, must be over 12” long, and wedge it between the flywheel and the block. You are going to pull up on the screwdriver to put upward pressure on the flywheel. Now take the largest hammer you have, I use a 5 lb hand maul, and while pulling up on the screwdriver with one hand, strike down hard and SQUARELY, I REPEAT SQUARELY on the head of the bolt. If done right the jarring action of the hammer should release the flywheel from the crankshaft. WARNING: If you do not hit squarely on the bolt there is a risk of damaging the bolt or flywheel. Try at your own risk.
https://www.mymowerparts.com/pdf/Ko...urage-SV470-SV480-SV530-SV540-SV590-SV600.pdf