Adjusting Choke Piston
- Block the throttle valve open.
- Loosen the clamp B.
- Hold the choke valve closed.
- Turn the clamp B clockwise until the piston moves all the way up in the cylinder and stops.
- Tighten the clamp B.
Is the Choke Working?
How do you know your choke is working OK?
With the engine cold, the choke valve should be closed. The fast idle may be keeping the valve from closing so you may need to open the throttle slightly.As the engine warms up, the choke valve will open. At full operating temperature, the choke valve should be fully opened.Test the thermostat – Remove the thermostat. Run cold water over the spring, then run hot water over the spring. You should see the spring wind, or unwind depending on the model.To adjust the thermostat – with the throttle open twist the thermostat until the choke valve closes, then give it another 1/8″ preload. Don’t worry about the index marks on the thermostat if there is any. Due to carburetor wear and retro fit thermostats, the index marks seldom work anymore.
