Small Engines (Lawn Mowers, etc.): B&S 17hp I/C OHV engine wont run, ohv engine, intake leak

Question
I have cleaned the carburator and the bowl is getting fuel. It will run as long as I cover the carb with my hand. Someone mentioned that the intake valve may be clogged. How do I check this?

Answer
I doubt the intake valve is closed.  This would typically result in low or no compression resulting in the engine not starting.
By covering the carb with your hand you are richening the fuel mix so the carb is too lean.  This can be caused by a clogged jet in the carb or an intake leak.  Check the intake gaskets and fasteners.  If all check fine then most likely the problem is still in the carb.
Did you use an air compressor to blow through the carb orfices?
Let me know.
Eric