Small Engines (Lawn Mowers, etc.): Lawn Mower wont start, craftsman lawn mower, piston rod

Question
I have a Craftsman Lawn Mower (Model 917.378490) that was making a strange sound in the engine area like something loose was rattling around in it. I turned it off and when I tried starting it back up the pull cord pulls but nothing happens. The flywheel turns but it doesn't catch onto anything. Should I just take it in to get repaired or is it something I can look into myself?
Thank you.

Answer
Hi Steve
It sounds like you may have sheared the flywheel key. If you remove the flywheel, you will be able to see if the key is there. If it is in good shape, remove the sparkplug and see if the piston is moving. If the blade turns with the flywheel and the piston is not moving, then you've got a broken piston rod. Hope this helps.