serious carb problem/ gas leak into intake

[swamp rat]

I'm not convinced you set your float correctly or you have a needle and seat not closing properly and the pressure from a non vented cap. The float level set properly will not allow any more gas to enter the carb, so if it didn't close the pressure from the tank could push the fuel into the carb then into the intake.

Big plus on pulling the plugs and taking the power off the coil and tapeing the wire up so it won't spark anywhere if it touches metal before turning the engine over to make sure the gas is cleared out. Then change the oil.