Out of a Clymer service manual
Tillotson diaphragm carburetor.
Initial carburetor adjustment is one
turn open from a lightly seated position
for both low and high speed mixture
screws. Make final adjustment with
engine warm and running. Adjust idle
speed screw so engine idles just below
speed mixture screw so engine will accelerate
cleanly without hesitation. Adjust
high speed mixture screw to obtain
optimum performance under cutting
load.