So I tried something we used to do with the Volkswagons when we wanted to establish whether low compression was due to worn piston rings, or leaky valves. I squirted an ounce of oil (gear oil in this case) into the spark plug hole. If the rings were worn, the oil would temporarily help them to seal, and raise the compression. I put the compression tester back in and tried it, and got 64 psi. Hmm, must be the rings.
I put the spark plug back in, and then figured I would see if the increased compression would make the fuel pump work any better. I pulled off the fuel line from the pump and hit the starter button, and sure enough, fuel pumped out. And the engine started! I was confused, but I put the fuel line back on, and tried it again. And the engine started again. I figured it would run for a little while, until the oil stopped sealing, so I ran the engine for a few minutes. It just kept running. Cool. I don't know exactly why that fixed it. Maybe it had a stuck piston ring and the gear oil freed it up.
I didn't have a good battery, so I couldn't ride the scooter. I put the body panels and seat back on, and figured I was done for the day. Then I remembered that it had a kick start! I gave a couple kicks, and it fired right up. Woo hoo! I cruised up and down the street a few times before I got bored. I got it up to 20 mph, but I still have throttle left. That was fun.
Linda and I made a movie to reenact the afternoon. It comes in different flavors. Warning, it's big. But it's worth it.
This is streaming video (9 Mb).
This is Windows AVI (6 Mb).
This is QuickTime (6 Mb).
Next on the list: get it registered, so it's legal.