Kawasaki engine in a Cub Cadet push mower

This one is for anyone who dove into the internals of a 179CC engine on a Cub Cadet push mower.

My neighbor gave me his mower that appeared to have a bad valve or broken ring. It smoked and stalled among other things.

I told him it was all or nothing and I was going to take the engine down to see what may be wrong. He abandoned it anyhow so there was nothing to loose.

I have rebuilt motorcycle engines before and I can get by on what I have picked up over the years but there was something in there that I can't figure out.

The crank shaft drives the cam shaft but off the cam shaft gear there is a smaller plastic gear that has what looks like a centrifugally operated device in the middle of it that is associated to a lever that comes out of the case and has a spring connected to it.

I can only figure this may be an engine load arraignment of sorts that increases engine speed under high load conditions. That is only a guess but I am curious as to exactly what it is.

Has anyone dipped into a Kawasaki engine that deep to know what this gear set up is all about?

Thanks for any assistance.