How to Adjust the Air-Fuel Mixture on a Vacuum Carburetor?

[Susan]

Vacuum carburetor air-fuel mixture adjustment method: 1. First check the tightness of all carburetor-related connections to ensure normal carburetor intake without air leaks or intake obstruction. 2. Turn the carburetor mixture screw clockwise all the way in, then turn it counterclockwise 2 turns. 3. Start the engine and let it warm up for 10 minutes until it reaches normal operating temperature. 4. Adjust the carburetor idle speed screw to achieve the lowest possible engine speed without stalling. 5. Repeatedly adjust the carburetor mixture screw left and right to reach maximum engine speed. 6. Repeat steps 4 and 5 until the engine idles smoothly. 7. Quickly twist the throttle handle to accelerate sharply, then release the throttle. Observe whether the engine accelerates and decelerates smoothly during this process. If smooth, the adjustment is successful; if not, repeat steps 4 through 6 until the engine acceleration and deceleration become smooth.