Tiger you really should invest in a new thinking cap as the old one appears to be defective.
The OP said fuel coming out the exhaust, leaking around the carb or fuel lines will not fill the crankcase. Only a carb that is leaking into its throat or lack compression causes this. And sheared flywheel key could shift the ignition timing but that is pretty rare.
And with crankcase flooded with fuel it going to be near impossible to start the engine.
