20. If you haven't already, remove the carburetor block from the back plate.
21. Repeat the sanding process.
22. Inspect the gasket surface of the carburetor. Mine was very rough.
23. Note that sanding is complicated by the arms at the ends of the throttle shaft. If you plan to sand it smooth, either remove the throttle assembly or find a flat surface narrower than the distance between the two arms. I was able to do the latter.