Small Engines (Lawn Mowers, etc.): Lawn Mower wont start, tecumseh engine, fuel jet


Question
I have a Murray push mower with a 6.25 HP Tecumseh engine.  

Week 1 - mower won't start.  Change oil, replace fuel. Won't start.  Clean float bowl & main fuel jet - mower starts & runs - Hooray!!

Week 2 - mower won't start AGAIN.  Replace air filter, spark plug - mower starts & runs - Hooray!!

Week 3 - mower won't start AGAIN.  Uh, put gas in it - can't think of anything else.  

My question is - who gets the bullet, me or the mower?

Any ideas?

Please talk to me like I'm a small child as I know very close to nothing about mowers/small engines.  

Answer
 Hello Jo Anne:

 Follow the Engine Brake/Shut Off Cable to the Connection Point on the Engine Block. Remove the Cover and have someone Operate the Handle. Does the Prong Move Completely away from the Stop Switch? If that is working Properly , then you may have Trash in the Tank and Carb that is being Disturbed each time you Work on the Mower. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John