Riddle Me This

I'm tuning my carb this morning and when things are about perfect the car shuts off. I try and restart it and it fires up, a second later the car fills up with electrical fire smoke and dies. Once the smoke cleared and I got under the dash the black wire going to the flasher is toast, insulation burned off all the way up as far as I can see. I pull the flasher down, make sure none of the exposed wiring is hitting anything and the car fires right up and runs. I'm assuming it grounded out against something and while cranking the car over it became part of that circuit. Thoughts before I dig into it tomorrow?

Thanks,
Jim