crankshaft pulley wobbles on 8N

[simonmeridew]

Looking from the side the crankshaft pulley is wobbling suddenly(my son uses the tractor now) and we want to repair it, but want to know what to expect, since taking off the hood disables the tractor till it's fixed, and it's used daily. I don't know why it's wobbling now. Can it just be pounded straight again or new parts. We want to have parts ready. It's been a while since I had the pulley off and I don't remember, is it pressed on with a keyway or woodruff key or does the nut just hold it on? Any help would be appreciated
simonmeridew

 

[Soundguy]

first find out why the wobble.. is it loose or bent.

old one is thin metal.. new ones are billet usually.

soundguy