If the cap contacts are 1/4" above the rotor, you have a serious problem. The rotor should spin within a few thousandths of the cap terminals, and the gap that is jumped should be very short. If you're jumping a 1/4" gap inside the cap, that's several times the plug gap. I'm surprised the engine runs at all with that much voltage loss before the spark gets to the cylinder. It's probably got a horrendous miss under load, right?
Jerry

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