IBNFSHN is right.

Not hard...you will need a flywheel puller....DO NOT try to do it with an automotive type...the one with clamps...you can bust the flywheel with those....you will need the screw in type. Many stores like napa, orielys, autozone, crowburlinggame, and the such have them...Other than that you just un screw the old on and put the new on...MAKE sure you watch the routing of your wires...as the flywheel will punish them in a hurry if you don't. Anyone with a little experience can do a stator though. Why did it go bad?? Make sure to check the rectifier...as one of them going bad can cause a stator to go south.

I'm going off the ones I've done....you may or may not need a puller. Depends on how old it is. Just don't beat and bang on it. I just remembered some old inline mercs I've worked on...the flywheel just unbolted and came right off.