After replacing the cylinder head, 20 hp Briggs and Stratton won't start.

After I replaced cylinder head gasket, I did check both push rods are metal, I did lash .006 feeler gap.
I did jump the battery, my briggs and Stratton 20 hp engine still won't start. .???
I did check oil and carburetor is cleaned.
I can not think how to find what wrong!
Please help me.

After replacing the cylinder head, 20 hp Briggs and Stratton won't start.