Small Engines (Lawn Mowers, etc.): Tecumseh Engine Question, broken rod

Question

Engine I have an MTD Riding Mower / Tractor with a 17hp Tecumseh Engine.  Last week it stopped running suddenly.  I used a socket wrench to try to turn the nut on the top of the engine and is stops at the same place each time.   Could you let me know if you believe this is fixable?  I don't mind working on the engine myself but don't know where to start.  Can you give me some tips?  See the picture for more definition.

I would really appreciate your help!

Thanks in advance!

Mike

Answer
If the engine will turn back and forth but stop at a certain point, then probably you've broken a rod.  This is fixable about half the time.  As long as the block is okay and the governor wasn't destroyed, then it would probably be worth rebuilding.  You have to determine why this happened if it did break a rod.  Usually it's from either gas in the oil or low or broken down oil.  

You can pull the spark plug and put a wooden dowel in the cylinder and see if the piston moves up and down while you turn the engine.  If not, then it's a busted rod.  The engine would need to come apart to determine the extent of the damage.  Let me know if you have any questions.  Thanks, PK.