from your posted service manuel, on page C-13, i will describe the only screws that adjust something, and i will refrence the number and explain it's purpose.
#35: this is your idle speed screw. by adjusting this, your idle speedwill go up or down. this will only adjust your idle speed.
#34: this is your fuel mixture screw. this screw will control the amount of fuel that goes through the pilot jet circuit of the carb. the pilot circuit controls the fuel mixture at idle, and also fuel mixture from 0 to 1/3 throttle opening. the fuel mixture screw will also fine tune your throttle response.
#25: float bowl drain screw. this screw's only purpose is to drain the fuel from the carb. this is used only in prep for storage to empty the carb of all it's fuel.
which other screws are you refering to? these are the only screws that will change your idle/performance. there are no others that will effect the engine/fuel delivery.
if you believe i have helped, pleae click "ACCEPT" so i can get credit for your aide.
thanks! and pleae let me know which other screws you are tyaalking about if you have extras.