I just spoke with my brother to tell him of the progress with this. He said, "I forgot to tell you; that's not the original carburetor. The original was a diapragm carb, and it always leaked, so I put this one on. It's from a really old Sears generator. It's back from the time Craftsman equipment was painted blue."
I don't know the vintage of the Craftsman engine he installed in this edger (it's an old Little Wonder edger - really well-made), but I have an old 4 HP Tecumseh that I took off of my Troy-Bilt chipper that's not being used, so we're going to get this engine going and install it.
If I get a chance, I'll post a picture of this carb. I've never seen one with a vent tube like this one has.