You aren't bad enough. Make sure you have a decent puller and bolts, then give it heck. Tighten that puller till it is about to break, then tighten it some more. And then tighten it some more. If it still hasn't popped, lift and whack as described. But don't pound on it with a sledge. It's the shock that does it, not the bash. WD-40 and all those other mouse milks won't help. It can't get into the tapers which are locked together tighter than tight. BTW, some of those cheap balancer pullers with a skinny coarse thread pressure bolt are not a "decent" puller. I believe the factory puller has a 3/4" diameter SAE hardened bolt. Outboard shops have no trouble at all getting flywheels off.....if they have the proper equipment.