Well its not really a carburetor. It doesn’t have a butterfly to control the air, a low and high speed circuit for the fuel, or a float bowl the maintain a constant pressure as the fuel level drops in the tank. And the mixture screw is the fuel shut off. Fuel mixer is a better description. So for the reasons above, an adjustment will likely be necessary when changing speed as well as when your not, if your running it for any length of time.  Tubs