Re: these things suck
Once you drown the plug it can give you a spark while it is out in the air but not fire when under the stress of compression. It just goes to the path of least resistance.
I keep new plugs in a drawer for just such occasions.
Here is what I would do- spin the engine over for a bit with no plug in and fuel off. Put the plug in /choke off / wide open throttle and try to start it. If it fires and stalls - repeat with carb at idle setting.
Since the float is suspect, you might take the carb off and see if it drips fuel before you do the above.