1. Drain the fuel tank.
2. Disconnect the fuel line and remove the air-fuel mixture screw.
3. Place a piece of stiff wire into the idle mixture screw hole, and adjust it until the engine stops running.
4. Now rotate the idle mixture screw clockwise until the engine idles smoothly.
5. Reconnect the fuel line.
6. Check the engine idle with a vacuum gauge; the reading should be within the manufacturer’s specifications.
7. Adjust the primary air-fuel mixture screws to the manufacturer’s specifications.
8. Test drive the tractor.
9. Adjust the secondary air-fuel mixture screws, slowly rotating each one clockwise until the engine runs smoothly.
10. Check for idling speed and engine performance.
11. Adjust the idle speed as required.
12. Reconnect the fuel tank.
13. Check the tractor performance.
By following these steps, you should be able to successfully adjust the carburetor on your Massey Ferguson tractor. Make sure to follow the manufacturer’s instructions closely and to use the appropriate tools and safety equipment while making adjustments to the carburetor.