Small Engine Troubleshooting Problems? Ask a Mechanic Now.
This unit does not have brushes, nor an AVR. This is a capacitor regulated system.
The most likely cause of your issue is a bad capacitor.
You're right. I looked at the parts diagram a half dozen times, and did not see the brushes. But there is a footnote at the bottom of the page that says the brushes are not shown. My bad.
I did check with some contacts of mine, and I was unable to locate them at all.