Ok, so first of all that tiny little recessed brass screw on top is the idle mixture screw. If it was hard to start (and especially if not sprightly when you rev it) a half a turn out from factory is a good thing.
My suggestion for the sticking is to apply grease on the rotary barrel - undo the two phillips head screws, and pull the whole top plastic bit off.
There will be a small 1cm long cylinder underneath it (with a thin brass rod in the middle. Thats what you see black in the carby throat - the way these work is that external lump on the slider lifts up the power needle - its a variable jet. lube up the cylinder and check for any swarf from the factory.
Normally that will fix it, but sometimes with these they are hopeless. Is this the 5in1 trimmer with the hedger, saw, edger etc? Black and red motor? If so, they use a 'sunseeker' branded carb - lowest of the low. It will be stamped sunseeker somewhere on the carb
Despite multiple attempts, I couldn't get the one I was tasked with to work
Please also bear in mind these are a straight knock off of a walbro wyj carby, if all else fails its sub $25 on ebay to throw a whole carby on.
