Small Engines (Lawn Mowers, etc.): Primer, passageways, carburetor

Question
Lawnmower primer works well to start but after mower runs for a while, 5 minutes, the primer bulb becomes pushed in and the engine dies.  When I let the mower sit for about 10 minutes the primer bulb inflates and is ready to start again but only about 5 minutes.  What do you think the problem is?

Answer
James
You have a problem with the carburetor sounds like the idle port is obstructed causing a vacuum after it warms up rebuild the carb or take it apart and clean it really good. Be careful about using compressed air as you may blow parts out that are so small you wont see them fly away.Use a good carb cleaner and inspect all the holes tubes vents and passageways.