"In the above diagram you can
"In the above diagram you can see the coil at top middle, the left side is the positive terminal. There are only 2 wires, if you follow the lighter color one (should purple/black?) you can see it goes down to the starter solenoid, this should not be live while running, if it is then most likely a defective solenoid. The other wire should be purple/red and if you follow it down it splices into 2 purple wire, one goes down to the voltage regulator, the other goes to your dash, this is the wire that comes from the run position on the ignition switch. If your step dad wired in a kill switch properly it would have went into this purple wire somewhere near the helm or right on it. I can really only 3 things that might cause your problem, the ignition switch itself (you replaced already), the starter solenoid leaving that line with 12v while running or possibly the voltage regulator, if it's either of the last 2 then your kill switch won't help you anymore than the ignition switch. That's why you need to separate the 2 wires on the pos side of the coil and see which one is keeping the ignition live. You need a multimeter ot at the very least a test light. If you think this may be beyond your abilities then possibly you have a friend that can help or it's off to shop?"