Small Engines (Lawn Mowers, etc.): Blower quits when it gets warmed up, sears craftsman, gas mixture

Question
I have a Sears Craftsman blower.  It takes an oil/gas mixture.  It starts fine, and then after about 5 minutes it starts to die off (lose power) and then eventually quits.  It won't restart until after some time (when it has cooled down).  Where should I start looking?

I replaced the spark plug, but that did not help.  

Answer
 Hello Rick:

 All Metals expand when Heated. The Cylinder is Expanding away from the Rings and that is evident from the Statement, "Starts to Die Off (lose power). Sorry for the Bad News.  Hope this Helps.

 Good Luck

 Respectfully

 John