Small Engines (Lawn Mowers, etc.): Lawnmower issue, oil level, white smoke

Question
Finally got around to sharpening my lawnmower blade today. Tipped mower forward against shed wall to access blade. Stupidly left it in that position all day. When I put the blade back on and brought it down the engine is now struggling to run and blowing white smoke. Any thoughts?

Answer
Most likely engine oil seaped inside the cylinder.  When you went to start the mower some of the oil started burning and some got passed the exhaust valve and into the muffler.

First, check the oil level.  Next remove the spark plug and spray carb cleaner or brake cleaner into the cylinder to thin the oil.  Pull the string and push as much oil out of the cylinder; this may be messy.  Do this several times to clean the cylinder as much as possible.  Check the air filter to make sure it is not soaked with oil.

By this time you can use the mower but it may still smoke for a while until the oil burns out of the muffler.  You can remove the muffler and clean/soak in parts cleaner but it is very difficult to remove all the oil so expect some smoking.  The other option is to replace the muffler but they can be expensive.

Finally, after running a tank of gas through the mower I would replace the spark plug.  I'd go ahead and buy a new plug to have on hand in case the current plug fouls.

Let me know if this helps.
Eric