My two stroke motorcross builder buddy has described in
The past a similar condition where the case just gets full of gas and unless fully
Drained just won't start. So yea I think that's what happened.
Turn off the petcock when ya finish putting back together and turn it on just before you are starting it.
It might be wise to have the carb off the intake as a trial and open the
Petcock with the carb upright and make sure the float is working perfectly and not dumping gas.