Small Engines (Lawn Mowers, etc.): MTD/B&S hard crank wont start, starter solenoid, battery terminals


Question
1996 MTD with 46" deck, bought used.  Cut last summer with no problems.  Replaced plugs, air filter, starter solenoid, oil, and it started and ran fine.
This year the mower was turning over hard, and would not stay running unless the choke was all the way out.  It acted as if the electrical system had been shorted out if the choke was pushed in a bit. Prior to installing a new battery I jumped the mower off twice with my truck (running). Having now replaced the battery with a direct replacement, it will barely turn over, 1/3 of a rotation. It won't start on a jump now, either. When rotating the flywheel by hand, it sounds like a gear is turning.
Help! My yard is out of control!!!  

Answer
Clean the battery terminals.  Dis-connect the terminals and clean with a wire brush.

I would also check the plastic starter gear.  Sometimes the gears wear and tend to stick causing cranking difficulties.

FYI, I rarely find bad starter motors.  It is usually dirty terminals or a wore starter gear.

Let me know what you find.
Eric