TH is top handle. The early model 020AV came in a top handle model, as well as a rear handle AVP model. These saws are from the early 1970s. No books on them that I can find, the Stihl web site user manuals starts with the 020T model (that saw has only the L screw, no H). This saw is earlier than my experience with the later modern Stihls. I figured someone here would know how to pre-set the carb an old 020AV like this one.
This one is all metal, and the precursor to the later early model 020T which was half plastic. I will probably sell it becasue I cannot see using it (I do not climb any more). Most saws back then ran 25:1 gas/oil mix, but several on here say that you can run them fine on 50:1 new and better oils. I still dump in 25:1 on this one though. It still has the tag on the back with instructions for how to start it.
I did notice the fast idle when cold and setteling down when it gets warm thing. I figured maybe it was the H & L settings, and that is why I wanted to know what the L& H screw settins are for it. This one is near new from the looks of it. Was in a guy's Winnebago and he used it for camping twice a year. Has an all but new bar and chain on it, and little if any chips in the paint. I looked at the piston and there is no scoring, and the plug is nice and tan.
Anyway, thanks for the tuning tips. :greenchainsaw: