Ed, You're welcome.
I am thinking about the pilot screw kit, err the air mixture screw right now. Called a Kit because you cannot just buy one of the components. They are: a needle screw, a spring, a tiny metal washer and an equally small o-ring. Did you remove these at all? If so ensure that all the components are in place in the proper order for the left carb.
When you removed the jets did any of them look mucked up? Like a screw driver slipped off the notch? A bit of metal may have flaked free and gotten lodged in a passageway...
Your issue seems to be asymetrical, thus these various thoughts on why one carb would not work given that all the electronics affect each piston equally, except for the ignition coil, spark plugs, and spark plug wires, that is.
Good luck and I hope you get her fixed up real soon.
