How do you remove a frozen woodruff key from a Yamaha F150?

Answer 1

Plan A: Drive down the side closest to the base plate with a large pin punch and a heavy hammer or small sledge. This will drive up the top side of the key. Keep in mind the the key sits in a slot that is the exact same shape as the key itself, so if one side goes down, the other will come up. Next, insert a cold chisel or similar tool in the corner between the top of the key and the drive shaft and use the hammer to drive the key out. A screwdriver or other plastic-handled tool will not generate enough force to get the job done.

Plan B: If Plan A doesn't work, obtain a Dremel with flex extention. Use a small metal cut-off disc to make a precise cut down the middle of the frozen key. Cut all the way down to the bottom. It's okay to over-cut into the drive shaft slightly. Next, use cutting pliers to squeeze and collapse the two sides of the key toward the center. Now it will pull right out. Obviously you must replace the key with a new one.

I have used both techniques successfully, but sometimes Plan A isn't enough to free a rusty or mangled woodruff key. For these jobs, Plan B is quick and effective. You just need the right tool (Dremel with flex extention and cut-off disc).