Happened to me last month,first time in six years. Mine was gas. Had choke on to start,backed out of shed, put on antennas, closed choke. Drove out front and gas was running off the bottom of the cowling by radiator. Then saw gas track lines down the right inside cowling for air breather. Turned off, restarted and blipped throttle hard a couple of times and dripping stopped. Have driven daily almost since then and no recurrences. When having new tires mounted talked to service manager and he also said probably just something in the carbs that flooded and then cleared out with hard throttle. Had a new fuel filter put on last year during valve clearance check. I'd keep my eye on it before letting shop search for something that might not occur again.