Small Engines (Lawn Mowers, etc.): Briggs & Stratton Engine Start, briggs stratton engine, briggs stratton

Question
Hi...
 I have a Briggs & Stratton Engine 5BSXS-5012 VP on a Sears LT-1000
Lawn Tractor.  It's almost 4 years old, and runs like a top after I get
it started.  
 My problem is that it no longer starts like it used to.  I even
bought a new battery with the same CCA Rating as the original battery that
came on the tractor which worked perfectly each and every time.  Now, I
have to manually rotate the Engine-Shaft guard to relieve pressure on
the cylinders.  (At least that's what I think is happening) After doing
this, the engine usually starts with help from a battery charger.  This
is the 3rd battery (New) that I've tried; so I don't think the problem
is the battery.
 What could have happened to the engine over the last year or so that
causes it to be more difficult to start ?  I change the oil and filters
twice per year, and the oil still looks new to me.
Thank You !
Ed VA


Answer
Cables will corrode, internally, and cause execessive current loss.  I would start by dis-connecting the battery cables and cleaning the battery terminals and cable ends with a wirebrush to ensure the connection is solid.

Does the oil smell like gas or is the oil level too high?  Will the engine turn over freely with the spark plug(s) removed?
Let me know.
Eric