How did the oil get there? How much oil is in the carb? Did you tilt the mower on its side? Is the air filter soaked with oil? Does it smoke when it runs? Check your oil level and make sure it is not overfilled. Will the mower run? If it will run fine the oil will burn off. If it is saturated with oil you may need to remove the carb and clean it. There could be other issues like a blown head gasket as well. Good luck.
