New high tension wire and insulation installed, old one was stiff as a board.You likely have a bad coil or bad cap. You can try an automotive cap or another small engine cap mounted externally to see if it makes any difference. Isn't the cap wire also the kill switch wire?
Also have you checked the HT lead from the coil? If you unscrew it from the coil tower it should read zero ohms to the center electrode of the plug. Also look fro cracks/damage to the wire. You may also see issues with your drill motor in a dark garage/room.
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