If we are talking simple, then you could try a syringe and timing light.
Fill the syringe with a little fuel and, with the air filter off and the engine in splutter mode, spray a bit of fuel down the carb to see if it continues to splutter or picks up. That should tell you if it is fuel starvation. No peeping down the carb to watch where the fuel goes, mind, you don't want to lose your eyebrows...
Second, when you use a timing light it doesn't just show the timing, it shows whether the ignition is still firing. When you rev the engine you should see the timing change in a smooth manner. If the flash disappears then the problem is in the distributor/coil/leads area, if the timing changes unexpectedly then the problem might be the mechanical or vacuum timing mechanisms.
I always remember that the problem is probably not what we think it is, because if it were then we would have fixed it already. :-D
trevor