I just got one from eBay for under $10 shipped to use on my Husqvarna 125L string trimmer. After about 5min of tuning all I can say it's like a whole different machine! Out of the box it never idled consistently and throttle response was always finicky. The thing purrs now, will set and idle unattended with nice snappy throttle response. This particular make/model has little splined screws for the L and H adjustments. Same as many Sears/AYP/Poulan products FWIW.
Joel
Joel