toro 620z mower

Just bought this mower has a 20hp onan? 95 or 96 . Started up fine when I picked it up, now at home it rurns over but won't fire smells floode even though I had throttle all the way down and choke on. It ran fine yesterday. Don't know if it's the solenoid, the carb, the fuel line. I'm gonna burn up my starter before I figure it out. Need help.