The purpose of the automatic choke is to temporarily richen the air/fuel mixture to the engine by closing the choke valve when the engine is cold. By shutting the choke valve you are effectively choking the engine by reducing the amount of air which is allowed to enter the carburetor. This then enables the air/fuel mixture to be ignited sooner (faster).
- Check the choke housing its hoses for any leaks, cracks or other damage.
- Check that the middle mark on the thermostatic case is aligned with the mark on the coil housing.
Loosen only the three screws around the outside edge of the case. Do not loosen the bolt at the center of the case because it will allow coolant to come out.
- Remove the top of the air cleaner.
- With the engine cold and turned off, press down on the gas pedal and release it. The small valve in the center of the carburetor bore should be almost completely closed.
- Run the engine until it reaches normal operating temperature, then check that the choke valve has opened up.
- Reinstall the top of the air cleaner.