Small Engines (Lawn Mowers, etc.): Ryobi BC30 Weedtrimmer problem, plastic gas tank, spark arrestor

Question
I can get the weedtrimmer to start with the choke in the "A" position which restricts air flow to the carburator.  As soon as the choke is moved to the "B" position which opens the flap just a little, the trimmer stalls every time, even if I let it warm up a long time (e.g., 2-3 minutes).  I took the plastic gas tank off, emptied the gas, made sure all the gas lines were clear, and then reassembled the gas tank and lines.  After filling with gas, I could still only get the trimmer to start in the "A" (cold start) position.  I would appreciate any advice.

Rob

Answer
 Hello Rob:

 Remove the Muffler and Check the Exhaust Port for Blockage. Check the Muffler and the Spark Arrestor Screen for Blockage. The Spark Arrestor is in the Muffler. If these are Clear of Blockage, then the Carburator May need Cleaning and Rebuilding. I am here if you Require more Assistance. Hope this Helps. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John