With the help of my daughters boyfriend, I finished rebuilding the leaking cylinder last night. We installed it back on the machine, and he was very interested on how it works. So this afternoon, with Joe here, I fired it up. We ran the cylinders through the cycles, getting out the air. Joe was still scratching his head, trying to figure just what did what. So I pointed a few things out, fired it up and I ran it through again.
I have figured out that the cylinders were leaking from hard rubber O-rings, most likely caused by overheating the machine. There are specific instructions telling you how to avoid that.
We also discovered that the carburetor float must be sticking, because gas dripped from the carburetor as soon as I turned it on. I may try to clean it, but if not, someone can fuss with that later.