Small Engines (Lawn Mowers, etc.): lawn mower will no longer start, briggs and stratton, spark plug wire

Question
Hi Michael,
 I was helping my girlfriend's nieghbor who's husband is very sick. They have an old yard machines mower with a 4hp briggs and stratton motor. Being an older mower, she was afraid it would not start this year, so I cleaned the air filter checked the oil and spark plug and got it running. I was mowing the yard for her when it ran out of the gas it had left over from last year. I put fresh gas into it, primed it, and it started up easily and ran fine again. None of the cables work so they have been shutting it down by pulling the spark plug wire off. I went to shut it off to move to the back yard and of course I was getting shocked a bit and dropped the wire. I tried to grab the wire and dropped it again. It was kind of running and kind of quitting because the wire was dangling near the plug. I didn't really realize, but apparently it may have made a popping noise along with the sputtering. After this I tried to start it again and it would not start. It is definitely still getting spark and I took the air filter off and when I push the primer bulb it is still putting fuel into the carb. I took the flywheel off to check the keyway and although the key looked fine I replaced it. I took the head cover(?) off and the piston and such is indeed moving. I'm not sure if it is normal, but when I turn the blade it turns fairly easily by hand. Any ideas on what pulling and dropping the plug wire may have caused? Thanks for you help.

Answer
Hi Michael,

You have certainly done all the right things to discover the problem.  What happened with the plug wire should not have caused a problem.  If you have timed spark and fuel, the engine should run.  Check the compression.  The engine should not turn over easily with the spark plug installed.  

Let me know what you find.
Michael