It is usually a small metal part that sits on top of the engine, and there should be a fuel line connected to it.
2. Locate the adjustment screws.
There will be two screws, one for the idle speed and one for the mixture:
* The idle speed screw is usually located on the side of the carburetor and has a small spring attached to it.
* The mixture screw is usually located on the top of the carburetor and has a small plastic cap over it.
3. Start the engine and let it reach operating temperature.
This will ensure the engine is running at its normal speed and the adjustments will be accurate.
4. Adjust the idle speed.
Turn the idle speed screw clockwise to increase the idle speed or counterclockwise to decrease it. The engine should run smoothly and without hesitation when you release the throttle.
5. Adjust the mixture.
Turn the mixture screw clockwise to lean out the mixture (reduce the amount of fuel) or counterclockwise to richen the mixture (increase the amount of fuel). The engine should run smoothly without any black smoke coming from the exhaust.
6. Fine-tune the carburetor.
Make small adjustments to the idle speed and mixture screws until you find the combination that gives the best performance.
