I just washed up my three year old rototiller and I found a couple of stone chips and I'll explain how I'm going to fix them.
You can see the little rusty stone chip about the size of a small pencil eraser.. see arrow. This particular rust spot also has a crack in the paint about 1/16 of an inch long beside the rust spot. I called Auto Zone and they used to stock a type of abrasive looking pencil pointed on the end that I would have used to get that rust spot out. Instead I got my dremel tool out and took a real fine pointed stone and went zip-zip and the rust is gone. I barely took the rust off because this stone is so fine that you couldn't take metal off if you bore right down on it. The paint on this tiller is pretty thick. When John Deere opens Monday I'll go get some touch up paint for the 647.
Just another picture of the rust spot.
I layed the sharpie beside the stone and the dremel for size comparison.
Here it is after I hit it with the dremel, and to repeat myself, I barely touched it. It looks nice and shiny now, ready for touch up paint. Plus, I got that crack out that was beside it.