I see posts about turning up the governor. Is that the same as backing off the high speed stop screw?
By the way, I have a simple method for adjusting the idle screw- cheating really. Once I get the idle screw turned in to the lowest idle possible I leave it there. Then I cut a short piece of small dia. hose,1/4" or so, that fits snugly over the end of the idle screw at a length that fits my idle speed requirement. You need to do a little trial and error but it is easy. If I change fuel adjustment I just slip another piece of hose over the screw end. This has worked for me for the past 5 yrs or more.
By the way, I have a simple method for adjusting the idle screw- cheating really. Once I get the idle screw turned in to the lowest idle possible I leave it there. Then I cut a short piece of small dia. hose,1/4" or so, that fits snugly over the end of the idle screw at a length that fits my idle speed requirement. You need to do a little trial and error but it is easy. If I change fuel adjustment I just slip another piece of hose over the screw end. This has worked for me for the past 5 yrs or more.