Pull the exhaust off and see if there is anything in there ... You may have just FLOODED it and what you saw coming out of the Flange (1. it should be tight enough that nothing CAN leak out) may have been Gas mixxed with carbon from the piston .... check and see if you can find out what it is ...
Im gonna say your Jetting may be off too if you can get it running with your choke but not with the throttle ...