Small Engines (Lawn Mowers, etc.): B & S engine starts but wont keep running., briggs stratton engine, briggs stratton

Question
I have a craftsman lawnmower with a Briggs & Stratton Engine (model# 123K02-0258-E1). Problem being that the engine will start after I prime it but will die after about 5 seconds.  I have replaced the gas, changed the oil, cleaned the carb a few times, rebuilt the carb with new seals/etc.., inspected/replaced all gaskets, installed a new spark plug, checked the float, and replaced the fuel line.  The carb is getting fuel, but the engine is not getting any for some reason. I tried putting my hand over the carb intake like you have said to try in other posts and the engine does not start this way. I checked the seals between the carb and the engine and they appear to be fine. Any help with this would be appreciated.  

Answer
 Hello Brian:

 Did you Soak the Disassembled Carburetor Overnight in Carburetor Cleaner? If Not the Carburetor May Not be Clean. Over the Years I have Found that a Small Engine Carburetor Cannot be Properly Cleaned Unless Soaked. Then Blow Out the Passages with Compressed Air and Install New Kit. From the Breakdown/IPL, I see you have the B&S Carburetor Number 498170. If this carburetor has Any Trash/Varnish in the Main Jet or Jet Passage, the Engine will Operate as you Described. Remove the Plug Wire from the Plug and Sharply Turn the Engine Reverse Rotation. Does the Engine have a Good, Strong KICK BACK? If yes then, the Compression is Supposed to be Good. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John