Just got my 24 coupe running. I'm not a mechanic. I'm a tinkerer. Starts and runs good on battery. Doesn't run smooth on magneto. Any suggestions?
Classic symptoms of improperly adjusted ignition coils or a weak magneto. If your lucky it is the former, the latter is a bit more difficult to repair properly. See if you can borrow a known set of properly rebuilt and adjusted coils to isolate the trouble.
Remove and check the magneto post for lint
I had the same issue when I bought my '27. It turned out to be a poor connection at the magneto post. Now it runs measurably better on mag then on battery (as it should).