Everyone always thinks it just has to be the carburetor when an engine misbehaves. That's not always the case, and I think you've covered that in this instance. Can you rig up a pressure check as I outlined? Do you have another ignition to try? If shipping both ways wasn't so expensive, I would say send it to me and I'd have a look at it. If you really are ready to "chuck it in the trash", I'll take it!
AV8TOR