Small Engines (Lawn Mowers, etc.): mower will not start, mtd mower, safety mechanisms

Question

wires My mtd mower model 13a6673g118 will not start.I replaced the carburetor a few years ago and it has been great for two years.  About a month ago I started to have trouble starting it.  It would take longer and longer to start it.  I had the battery tested and it was fine.  I put in a new spark plug and it started immediately but then next time nothing and it has been dead for two weeks.  My original thought was the solenoid and safety switches but when I tested the spark plug, I had a blue spark.  Does that mean the issue is not electrical and something within the engine?  If so, what should my next step be?  The engine will sometimes crank like its going to start but most times it does a half crank pause and another half crank (does that make sense?).  I decided to try one more thing before sending you an email.  I wanted to see if I recieved a spark when I did not sit on the seat/ press in clutch (safety mechanisms).  I was shocked and a little confused that I still had a spark on the spark plug.  I also noticed that two wires were messed with (prior to me getting the mower).  The wires were cut and then reattached.  I am not sure why.  I attached the pictures.  

Answer
Hi Kevin
It has been my experience that when the engine is only making half turns it is not getting enough energy to turn the engine fully,  so I would start with a new battery. The good battery may be discharging as it sits. Also, pull the spark plug out and see if you get a full rotation. Let me know what happens so we can go the next step.