I was on a hill yesterday and flipped my 36" mower on its top. I see no damage but there was oil leaking out of my air filter chamber. I see no other damage. I decided to quit using it that day, it was my last lawn and I was almost done anyway. after soaking up the oil where it was leaking, and apparently it stopped leaking once it was righted I started it to get it on my trailer. It spit out blue smoke and ran rough until I got it on the trailer. I shut it off and I was wondering, is that just oil that got in the fuel or is this a more serious problem. Should I take it in to a shop and have them check it out. Thanks for any help. Paul