Mike, take a close look at the ring in your second photo, It looks like it has been bent and twisted. Note that the arm is not coming off it square, but has been twisted. It looks like it has had some serious plier work on it. $4.95 is cheep insurance.

That style arm loosens up some times. Itake it off the carb, and use a small screwdriver as the punch and drive the flares back tight in the notches on the arm. My O.S. 52 four stroke has the same type arm and I couldn't figurre why the engine was not consistant around idle. I then noticed that the ring was chucking agack and forth on the hub. Loosen the set screw and then tighten thingsup on the bench block and you are good for another season.

I'm not a fan of using the punch on the throttle arm while it is still on the carb.It would be to easy to sip and cause some reall damage.

Don