Chris -
Just as John said, you have to replace the control magnet, the plunger, and the rivet/pin. You should also lubricate the track / pathway that the spin cam bar rides in while you're in there.
There are two ways to buy a control magnet - bare, or with plungers and rivets. Get the later, the part number is 89814.
To install, first you need to remove the old control magnet. Just remove the center screw and shimmy it off - you'll need to twist back and fourth while pulling up.
Then, cut the pin on the bent plunger. This will allow you to take the plunger off.
Take the new plunger from the kit, set it over the existing cam bar, and install the rivet and tinnerman through it and through the cam bar at the same time.
Position the new control magnet over the two plungers. You might want to clean the right side plunger to remove carbon, etc. Slide the magnet onto the shaft while keeping the plungers engaged inside the magnet. Then tighten the magnet and re-connect the wires.
If you get the wires confused, red goes on the left, yellow on the right. It doesn't matter where you put the white ones. Be sure to feed them properly through the hole in the magnet and use that black plastic collar they supply.
Sounds easy enough?
Gordon