Another problem?

Had a spare five mins today, so decided to kick her over and see how things are going. Opening the garage I noticed that a small of oil underneath the scooter, which smelled of gasoline and would appear to be coming from the carb fuel mix gromet. The bike kicked over, but for the first minute there was a fair amount of white smoke which then subsided. I think but I’m not 100% sure, that my petcock is damaged (other than the tip snapping off) its really stiff and I think its not completely closing all the way, therefore fuel is draining into the carb then leaking out when dormant. This is just a theory right now, I intend to check this by closing the fuel tap while the engine is running to see if it will die. If anyone else has any theories feel free to chip in.

I need to change the fuel tap anyway and my new one has arrived, so maybe this weekend