Small Engines (Lawn Mowers, etc.): b&s 5.5 HP wont start, blade, screw

Question
Hello.  My lawn mower died on me tonight.  I stopped for a break and when I went to pull the cord to start again, the cord wouldn't pull back smoothly.  The quicker/harder I pulled back, the more resistant it became (even to the point were it felt like it yanked it back out of my hand!)  It's only two years old and has never had problems starting before.  I thought it had just gotten hot so I gave it an hour to cool down, no help.  Any idears?

Answer
Hi Chris,

It sounds to me like the flywheel key has sheared.  This would have happened if an object was hit with the blade or if the blade was loose on it's mounting screw/s.  If you wish to do the repair, which is a bit involved, let me know and I will send directions.

Michael