Difficulty in mixture control

Adjusting OS 3H carburetor on OS 32 FX in an unstable condition because of some banish and dust clogging at the nozzle portion, I found out some physical tendency that the rate of muffler pressure affect on the A/F mixture at middle speed rotation. The diameter of the muffler pressure nipple affect on the mixture control,in relation with the fuel squeezing mechanism.They have much to do with the rotational condition, hi-middle-low transition.
In case I invite YS fuel pressurized regulating system, such kind of nervous and precise adjustment is not required, only the regulator adjsuting screw angular position is the key to control in addition to the lowest mixture. As for lowest mixture, I would often the best adjustin screw position when spining maneurver, stops or continues.
YS system does not require any sensitive adjustment except regulator, also muffler pressure nipple is replaced into closing hole screw.
I preferr YS system to ordinary muffler pressurizing fule supply however another manufacturer's motor is burdened on my model airplane.
My OS 25 LA motor has pressure nipple to invite it to YS regulator with good operation and response at any rotation, also this small motor has a history to be modified increasing main Schnurle port by myself following OS 25 FSR, and the operating performances are almost the same if used under 13,000 RPM, the advantage of LA model is lighter weight.