Cyclone,
On the carby you have one screw in the center of the plate, remove it and you will see a wire mesh in a recessed circle hole. Take out the mesh and replace it (cost about $3.00) or do what some people do just leave it out (I don't do it myself).
You will find that the trimmer will run better and then you will have to reset the low & high mixture screws. If you do a search on the forum you will find the settings or click the subscriptions in My Stuff at the top of the forum to get more detailed info.