Small Engines (Lawn Mowers, etc.): small engine cranks but wont stay running, engine cranks, fuel cap

Question
I have a weedeater gas blower.  I can get it to crank up, but after running about a couple of minutes it cuts off and will not start back up.  If i wait about 20 or 30 minutes it will crank again and then shut off again.

I replaced spark plug.

What could be the problem?

Answer
It sounds like you have a problem related to either heat or time.  Try this first.  Run the blower as usual, with the fuel cap loosened off a bit (to vent the tank).  If it continues to run, you will need to clean and/or replace the fuel tank vent (usually in the fuel cap).  If this has no effect, you may have an ignition problem.  When it quits, quickly remove the spark plug, connect it to the wire and ground the tip of the plug to check for spark.  If it has no spark, the ignition coil/module may be failing when it is warm.  Before you replace it, check to make sure the shut-off switch isn't causing the problem by disconnecting and re-checking for spark after the engine is warm.  Hope this helps.