Small Engines (Lawn Mowers, etc.): flywheel only turns quarter of a turn when trying to start, briggs and straton, murray riding mower

Question
I have a murray riding mower with a briggs and straton enging believe its a 42 inch cut the mower stopped suddenly during cutting when i tried to restart it made a large click noise the flywheel would only turn about a quarter of a turn trying to find out if the flywheel key could have sheered or did the enginge throw a bearing

Answer
I would start by removing the spark plug and checking to see if the enigne will turn over.  If it will not fully turn then remove the top engine shroud and see if there are any external parts that are binding.  Also, check the output shaft, bottom of the engine, to see if something is binding.

If you can't find anything external that is binding I would remove the head and check the piston and valves.  

Let me know what you find.

Eric