Small Engines (Lawn Mowers, etc.): running problem, adjustment screws, check fuel

Question
i have echo model 1501 weed trimmer--serial # 188642
it will start and run for about 20 seconds and dies - any suggestions?
thanks

Answer
I suggest cleaning the fuel system.  Start with the fuel cap, fuel tank, install new fuel filter.  Check fuel lines for leaks.  Remove carb and inspect the insulator block for warpage.  Disassemble carburetor and install carburetor kit.  Be sure to clean the small screen in the top side of the carburator.  Blow out with compressed air. Reassemble with all new gaskets.  Lightly seat adjustment screws.  Back off enough to start the engine and warm it up.  Adjust the high and low speed. Install mew air filter too.