1. Park the Massey Ferguson 65 in a flat, cleared area and shut off the engine. Open the hood and locate the carburetor.
2. Unscrew the idle speed screw on the side of the carburetor counter-clockwise with a screw control. Turn the idle speed screw one turn at a time until the engine runs smoothly when it is not under any kind of load.
3. Adjust the main jet needle valve on the side of the carburetor with a screwdriver. To increase the main jet needle valve means to increase the fuel mix and fuel delivery which increases engine power. Turn the main jet needle valve to increase it one quarter of a turn at a time until you are satisfied with engine performance.
4. Adjust the fuel mix adjustment screw on the side of the carburetor one quarter of a turn at a time. This adjusts the mixture of fuel and air that is delivered by the carburetor. The exhaust should become black or dark grayish when you increase the fuel mix adjustment.
5. Adjust the idle mix screw on the side of the carburetor. This will adjust the idle speed. Turn the idle mix screw one quarter of a turn at a time until you are satisfied with engine performance.
6. Close the hood and start the engine. Let it run for a few minutes to allow the carburetor to warm up and the adjustments to take effect.