Well, the petcock problem is fixed. The throttle is still bad, but that's not eve half of the problem now.
Unfortunately, I left my lovely "Lucia" outside my office for two days after I walked home from work. In the meanwhile, the rain and cold seemed to really pound away. When I arrived to fix the throttle, I found all the lines jammed tight. The clutch is about 75 percent engaged, and won't move into any other position. Both brake handles are jammed tight, and I can see that the front brake line is completely unravelled were it goes into the front wheel. After walking all that distance, I didn't have an allen wrench, so I couldn't disassemble my throttle.
Needless to say, however, I'm assuming ALL my cables are wrecked. On Monday, I will order a new set. I'll have to learn how to replace the cables throughout. Any advice/instructions would be greatly appreciated.
Also, anything else that you think I need to know would be useful, too. Don't worry about sending DETAILED instructions. I'm still learning about mopeds, so it could only help. It might also help someone later who has a similar problem if they read it.
Basically, I know the engine and the rest is fine. The engine turned over, but the clutch was jammed "on" and I had no gas (throttle problem), so the engine wouldn't start. But even as I pushed poor "Lucia" the nearly 3 miles home, she kept engaging and turning over the engine as I pushed (BTW, pushing a moped w/ the clutch engaged is a very, very, very tough job). So there is still spark and compression. The problem now seems limited to the cables: clutch, throttle, brakes. The throttle problem also is contained to the handle, since it moves fine in and out of the carburator opening. But turning the handle will still not move the cable.
Thanks again for all your help. I hate being grounded like this, but I've learned a valuable lesson. It may be cool to ride through a winter, but it's not cool to freeze your moped into oblivion. I won't ride (after fixing) until Spring. That's for sure.