Small Engines (Lawn Mowers, etc.): JD L111 b&s engine valve adjustment, engine valve adjustment, engine model type

Question
I have a John Deere L111.  I am having trouble starting it. Since the battery was 3 years old I replaced that. Needed it anyway.  Still won't start.  I replaced the selinoid and it seems like it wants to crank. The dealer suggested a starter.  I think it has something to do with the compression release.  Do you suggest a starter or valve adjustment?  If a valve adjustment is needed how is it done, or is it a dealer thing?  It's a Briggs and Stratton V-Twin 20 HP BG20319

Answer
Please get me the ENGINE MODEL, TYPE and CODE,number...It is located on a tag on top of the engine or stamped into one of the valve covers near the spark plug. I think valve adjustment...  Remove the spark plugs and try cranking it over...tell me what happens then... Does it crank over?? I will look forward to your reply

Dave R