W0: Some of Stihls carbs have limiter caps , others welch plugs limiting only adjustment of the High Speed and Idle Screws. Hopefully your unit has no restriction within these adjustments. My advice would be to remove both Hi & Lo jets and spray carb cleaner within the orifices. Also add some concentrated carb cleaner within fresh fuel approx 2 ounces. Let mixture sit 20 minutes then replace the jets and turn in the jets until they bottom (gentley) then turn both out 1-1/4 turns . Choke the carb and attempt starting as usual . Once you have it started keep it running until the saw will run without choke . Once warmed up adjust the low speed in or out till it will accelerate without hesitation . As for the Hi speed same procedure , normally I turn the screw counter clock wise to around 1-1/2 turns
at WOT until it begins to diesel or gallop then turn it in )leaner) just till it clears out . Once all this has been done you can set your idle speed to your liking . I usually set mine a little high to assist with Cold Starting and Idle . Remember any adjustments (Hi or Low) normally require readjustment to the Idle setting .

Note: Just a further note of info always ensure your fuel tank is full and your air cleaner clean before attempting any carb adjustments ...E .

Thanks E,

My leaf blower has both the Hi and Lo adjustments limited to only a quarter turn by plastic plugs so I can't remove them. It appears that the plugs are plastic with a screw driver slot in them and a small hole in the middle. I was afraid to try to force them past the stop, thinking there must be a way of removing them without breaking them. Do you know if this is possible?