Appreciate everyone’s comments on the spark problem. I’ve swapped the condensers between engines, which didn’t change anything. And checked primary and secondary coil windings resistance, which are correct and the same on both engines. (I also checked for continuity on both coil wires. They were both the same also, but I had no idea that coil wires had such high resistance. An interesting tidbit of new knowledge for me.)
I’m getting a new Pertronics. If it doesn’t solve the problem, I’ll have it on board as a spare.