1Take the air cleaner off some morning, before you start your engine.
2Look down the carburetor barrel at the choke. Does the butterfly valve seem to be closed?
3 If the butterfly isn't closed, step on the gas pedal a couple of times before you start the car; the valve should close. If your car has a manual choke (as opposed to an automatic choke), see whether the butterfly valve opens and closes when someone pushes the choke knob on the dashboard in and out.
4 With the emergency brake on and the gearshift in Park or Neutral, start the engine and let it run for a few minutes. By the time the car has warmed up, the butterfly should open so that you can see past it, down the barrel of the carburetor.
5 If the butterfly valve refuses to open or close, try wiggling it with your finger.