Just had the same thing happen on my lawn mower this weekend.
Root cause was needle valve in carb stuck open, flooding cylenders and crankcase with fuel.
Since you drained your bowl, and if you dont have a fuel shutoff, your needle probably stuck also.
I changed out my 12 year old carb, changed oil and filter, ran it for 15 minutes and changed oil and filter again. Also, when you first start it, there will be a lot of smoke. Dont be almarmed, it is just the oil that was forced into cylenders by the fuel, it will burn off in 5 minutes or so.
Runs good now.
Since you did not run it, most likely no damage other than stuck needle. Flush oil real good.
Just curious, do you have an electric fuel pump forcing fuel into the carb? Could be an unwanted effect of too much fuel.