When it comes to carb adjustments you start by screwing in all three needles (low, high, and idle screws), also when tighten the needles in don't don't over tighten just snug them so not the round the tips. Next turn all the screws out 3/4 of a turn which should allow you the Chain Saw to start, but you may have to keep hitting the throttle to keep it running due to the rough calibration. After the saw is running adjust the idle needle first in till the chain in the saw stops. hit the throttle quickly to check to see if the chain stops after revving up. Next it's time to adjust the low idle by turning the needle in till the engine responds quick to the throttle meaning that the there is no bogging down then power. Finally after all that fun it's time for the high idle needle here you want to hold the throttle wide open and adjust in till you hear the engine start to 2 stroke. 2 stroke may be hard to hear the first couple of times adjusting the carb to the engine but your listening for the engine to have just a little stutter or miss.
Another way is to have a tachometer which are sold at stihl dealer but cheaper at a baileyonline.com. One would adjust the idle to around 2800 to 3200 rpm this is the point in which the springs on clutch disengage. Then the low would still be done as above by sound. The high idle is normally set around 13500 rpm but I would call the a dealership to find out exactly, due to different specification on different model chainsaws.
Goodluck and have fun
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