Dog and spring
There are more than one style dog and spring in the recoils so make sure what you're looking for. On some, the end of the dog has a circular end that fits in a slot in the recoil and I've seen that slot (typically plastic) where it's been broken DAMHIK. If that's the setup you have, there's also a small tab and screw that holds the dog into the recoil assembly.
I've also swapped recoils between 4, 5 & 7 hp motors before. Only issue may be the alignment of the mounting holes. Some are rotated 45 degrees compared to others, but they still work.