2001 Mercury 15hp 4-stroke

[overboard]

Hey guys, I bought this kicker motor for my V20. I got a great deal on it because the lower unit is shot. I am looking to change it to a 20" shaft kicker. Where would you guys recomend getting parts for this? I hate buying something with problems but I couldn't pass the deal up. The reason the lower unit is shot is that the poor old guy changed the prop, didn't tighten everything up properly, and it vibrated the poor thing to death until the prop and and prop shaft fell out while trolling a local lake. Any suggestions on where to go about getting parts or imput on what to look for while doing the job would be appreciated. Anyone know what lower units will cross over with this motor?