Check your hall effect switch. you probably shorted it out by trying to run the engine with the ground on the carb. Most carbs are insulated from the cylinder by a composite material to stop the heat transfer. Attaching the ground there would be like completely disconnecting the ground. Then the spark would be forced to return from the engine case through the ignition pickup sensor. That has happened to me on an engine that I had a couple of years ago. I failed to connect the ground wire and blew the switch on the first start attempt.

Mark