Small Engines (Lawn Mowers, etc.): engine wont start, auto parts shop, battery cables

Question
Mr. Jones - I have Yard Machine (MTD) that's about 10 years old and with B&S 14.5 hp engine. It's been running pretty well for the past 10 years but now I am having small problems here and there. The latest problem is the engine is not turning. I can hear the starter working but the engine is not turning at all. In addition, I noticed the following - headlight is not turning on. I checked the bulbs and they still look good but no sign of light. I also tried to jump the batter with my car but nothing -- no engine turning and no lights. Last week, the same thing happened so I jumped it with my car and after a couple tries it worked. But not this time. I took the battery in to local auto parts shop and it showed 12.6 V -- it's only a year old. I am thinking it's either the starter or it's short circuited some where.... any thoughts you may have are greatly appreciated. Thank you in advance.

Answer
Did you dis-connect the battery cables and clean both the battery post and cable ends with a wirebrush?  Corrosion may not be visible but dirty connections can cause your problem.

Have you checked the starter gear?  Briggs uses plastic starter gears which wear over time.  Sometimes the gear get stuck causing the starter not to turn.

Let me know what you find.
Eric