I wish i could be more specific on what make, and model of craftsman riding mower i have but it is not close by. My question though is I believe a pretty general one. my mower was back firing alot, and then just stopped running. i went to do a full tune-up on it, and when i pulled the spark plug all the gas came out the spark plug hole? what most likely is the problem? being i am somewhat mechanically inclined could i repair it myself? and last of all if I needed to take it to a professional, approxiamately how much am i looking at to fix it???