Small Engines (Lawn Mowers, etc.): Sears Weedwacker flooding, sears weedwacker, high humidity

Question
22cc Sears weedwacker(20 years old) will start but will not remain running.  It immediately appears to flood out.  This is very odd since my lawnmower did the same thing.  We are having a period of very high humidity.  Can this have an affect on the gas.

Answer
 Hello Brewer:

 Remove the Muffler and Inspect the Exhaust Port for Carbon Blockage. Check the Spark Arrestor Screen in the Muffler for Blockage. This will cause the Engine to Flood Out. If these are Open, then Clean and Rebuild the Carburator. The Pulse Pump is Stuck and Allowing the Carburator to Flood. Hope this Helps. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John