Small Engines (Lawn Mowers, etc.): craftsman lawnmower, spark plug wire, oil level

Question
I have a 4 year old craftsman lawnmower
and when mowing my lawn the other day, everything was fine, i had gotten halfway through cutting when i had to shut off the lawn mower. i returned about 10-15 minutes later to continue, and when i re started the mower, their was a crunching sound coming from the motor, i turned the engine off. what could this be?  

Answer
Hi Damir,

A loose blade or the blade scraping on the deck?  Disconnect the spark plug wire and check it. Next, remove the spark plug and rotate the blade while listening and feeling for anything in the engine.  Check the oil level.

Let me know what you find.
Michael