360 runs great one day and then poorly the next

Need to find someone with an oscilloscope.
In the meantime,spray bottle with water,and wet the entire ignition system down while its running. Could be spark not following its intended path.
Found a cracked spark plug that way.

Had a center electrode come loose in a spark plug. That was hard to track down. Pull plug,hold up to look at gap and electrode looks normal.point it down and gap is closed.

Rotors burn through and will still run.it is a discoloration inside where it pushed on to distributor shaft.