gas leak

Sometimes the float gets stuck in the bowl, it's a pretty common problem. But usually when you take the carb apart it frees up. If it's all together right now, I would try tapping on the carb with something that won't damage it. Maybe a rubber mallet. Not too hard of course. If that doesn't work I'd inspect the needle and seat. It shouldn't have any groove on the rubber surface.

It won't start because you probably flooded it, turn off the gas and try it. Or take out the spark plug and clean it off.

If tapping the carb doesn't work try taking your carb off. Take off the bottom cover. Push the float pin out and remove the float and needle. Pull the needle off the float. Reconnect the fuel line on the gas tank to the carb. Push the needle into the seat by hand (black cone first) and turn on the fuel valve. Try not to push it up very hard at all, but use about the same amount of pressure as the float would make. If it leaks, its the needle, if not then its something else, check the float needle tab, make sure its properly assembled.

And if all that fails then the float level could just be set way off...