Small Engines (Lawn Mowers, etc.): Another Briggs & stratton will start but only runs for 3-4 Seconds, carburetor system, briggs stratton

Question
We have the same issue as the topic with the same title which was placed on 12-8-05.  But we don't have leaking from the carburetor.  We have checked the intake and the suction is great.  We have cleaned the carburetor.  The level of the fuel looks correct in the carburetor and the float works.  If we spray into the carburetor starter fluid then it runs for 3-4 seconds.  What else should we check?  It's the 8 hp model.  

Answer
How old is the engine?  If it starts on starter fluid then most likely the compression, ignition and timing are working fine.

This leaves only the carburetor system to be faulty.  Is the engine a vertical or horizontal shaft?
Do you have adjustment needles on the carb?
Did you use an air compressor when you cleaned the carburetor?
Let me know.
Eric