Fuel pressure reactions

If you don't touch the float setting, the fuel level in the bowl will increase as inlet pressure increases. That is because it requires slightly more force is required to close the needle, meaning the float must be further under. The technical terms are "droop" or "bias" of a proportional controller. This might be a simple way to tweak O/F ratio if you have an adjustable regulator. Of course, traditional carburetor adjustment is to set the fuel level at the factory setting and change jets or rod settings.