Small Engines (Lawn Mowers, etc.): Mower turns over but wont start, safety switches, hp 40

Question
Hi, I have a Murray 21B807 13.5 hp 40".  It will turn over, but won't start.  It is getting plenty of fuel, air filter is clean and the spark plug is in good shape.  Not sure of the year, but was told it's only a year or two old.  It was running fine last weekend.  

Thanks, Jeff in Texas

Answer
Hi Jeff,

You will need to determine if the problem is a lack of spark or a lack of fuel flow to the engine.  Right after it quits, remove the spark plug, reconnect the wire and lay it against the engine head.  Crank the engine over and watch for spark at the plug's electrode. If none, then you will need to check the safety switches, if equipped.  If they are good I would suspect a faulty ignition coil.

If spark is good, then try to start it while squirting fuel or starting fluid into the carb intake.  If it starts and you can keep it running by adding fuel, then the carb most likely has dirt, debris or gummed fuel inside.   
You will need to remove the carb, disassemble it, clean all the small internal openings and blow it out with compressed air.   Probe each and every hole with a small wire.   Adding a carb rebuild kit wouldn't hurt either.  

Let me know how you make out.
Michael