Oil sensor only causes beeper to sound or not, wont effect any ignition circuits. And as Racer stated no switches to be reset. You have a problem that is likely to go major.
2 & 5 are the same coil in timer base, trigger could be failing and firing the switchbox late thus causing them to foul out. It also could be a bad advance box as it effects the trigger bias to switchboxes
Wasting your time and money....either pull it down and fix it or part it out. Trigger most likely bad as cylinder had preignition and now has WOT misfire.
Wiring problem in control box or at motor cowl. When you pull back something is shorting ignition to ground(motor dies) and is apply ground to overheat horn for a second( the chirp)
