Small Engines (Lawn Mowers, etc.): mower run for a few seconds and stops, briggs and stratton, starter fluid

Question
? mower runs great for a few seconds if I spray starter fluid in the air filter, then just dies. Replaced spark plug,air filter was full of junk (cleaned, removed, also made sure air pipe to engine was not clogged), replace gas (gas line has lots of little cracks but does not leak, problem?). I assume that the armature magneto works because the engine does run, even though I can not see a spark? Carburetor is getting gas because I unscrewed the nut on bottom of it and gas comes out, took off mower looks fine, the thing that I think is the float moved up and down, I turned it upside down and pour gas into it and I went through the small pin opening.

Sears push mulching mower
Briggs and Stratton 4 cycle emgine
Model #123k02-0181-e1

Any help would go greatly appreciated.
Alex  

Answer
Classic dirty carb problem.  Have you removed, dis-assembled and cleaned the carburetor with compressed air from an air compressor?

There are several videos on YouTube showing how to clean mower carburetors.  Several of the videos just have you clean the carb with carb cleaner.  This works most of the time but for really dirty carbs an air compressor is a must.

Eric