Small Engines (Lawn Mowers, etc.): 5 hp Briggs & Stratton wont start, briggs stratton engine, briggs stratton

Question
I have a 5 hp Briggs & Stratton engine that wont start.  It has a good spark.  The only thing odd about it is that when i pull the starting cord, air goes in and then out of the carburetor.  This may be the problem or not.  I just need some suggestions of what the problem may be and how i could fix it.

Answer
have you had this running before?  if not  ?  it seems to sound to me a valve is stuck  open. to check this, pull plug, see if it has compression by  a gage, or simply hold your thumb over hole, as you pull.  if there is none,  you will need to remove cyclinder head and check valves.