How to clean, adjust, and fix common carburetor problems on a Stihl FS90 trimmer weedeater

We have been using several Stihl FS90R trimmers for years now. We currently use 10-12 trimmers divided among crews each year. I have found 2 common problems with these trimmers and would like to show you how to fix them. One problem is that there is a little screen inside the carburetor and after months of use, debris builds up on this screen and must be removed. I'll show you how to take apart the carburetor and clean this screen. The 2nd problem is that the carburetor needs adjustment. There is a high and low speed screw on the back of the carburetor and if your trimmer is running rough, or there is erratic idling, popping, or difficulty keeping the trimmer running, you can adjust the low speed screw until the trimmer runs smoothly. I've seen different types of carburetors on the FS90 trimmers. Some have adjustment screws that require a screwdriver and others require a hex driver or 5/32 socket. The adjustments to each of these carburetors are different. So it's best that you let your trimmer warm up and adjust the Low Speed screw slightly until your trimmer runs smoothly.