Spend $10.00 on Amazon and buy a new carburetor.I don't know the exact location of the leaking, it think the fuel drainage thing at the bottom was stuck, but the leak was definitely not from the air filter. Yes, there is an O ring in the carb. I have blown out the main jet with air and nothing is obstructing the fuel flow and the needle seems to be working correctly too. When choked, the engine revvs very high but once the choke is moved slightly, the rpms drop very suddenly and after about 6 seconds the engine dies.