An alternative to removing adjustment screws (and maybe not getting them reset to perfection). Get the engine good and hot, remove the air cleaner and spray lots of GumOut(TM) down thru the carb. It does tend to stall the engine so make sure youre good and hot first, when the engine stumbles too much wait a second and then when it catches spray again. Into all of the orifices and tubes sticking up – not just thru the air opening. My practice has been to do this every so often.
Doesnt hurt to also put a can of the same stuff into the gas tank.
There may well be other good/great cleaners out there but I know GumOut works!! GumOut is the best carb cleaner I have ever found.