Briggs & Stratton 20hp, 2 cyl. Yard tractor won't turn over at start-up. Do I need an engine assembly drawing?

Hi,
No you probably need a valve adjustment. The YouTube link is:
YouTube - Lawn Mower Repair Valve Adjustment V-Twin (http://www.youtube.com/watch?v=hGkn0jR9RJM)
Peace,
Clarke
PS Thank jsfocke for the first posting of the link.