81 40 hp mercury flywheel

Just bought 81 bass tracker with 40 hp mercury. Ran good when buying it, 1st time out was fine also, but 2nd time out was very hard to start. Thought I flooded it, finally got it started and it would idle but when I put it in gear to take off it would sputter then die. Tried to start again and the starter just hung up. Got it home and could only turn flywheel half way. Removed flywheel and magnets were broke and getting hung on stator. I thought easy fix, get new flywheel but I cant find one. Ebay had one for $300 but it sold while i was debating. My flywheel just has 2 magnets directly across from one another part #7912 a12 I believe (77 teeth) I'll try to attach pics. Can I replace magnets? If so where can I find them? Anyone know where to find used flywheel? Any ideas or suggestions would be greatly appreciated..BTW new member and really enjoy this place.