Patent attributes
A carburetor automatic control system in an engine includes, a temperature-sensitive operating device for operating a choke valve so that the choke valve is opened with a temperature increase of the engine and a governor for opening and closing a throttle valve to maintain a preset rotational speed of the engine. The governor device includes, a stepping motor opening and closing the throttle valve over a range from an idling opening degree to a fully opening degree, and an electronic control unit driving the stepping motor so that the rotational speed of the engine is maintained the preset speed. A relief mechanism is interposed between the choke valve and the temperature-sensitive operating device, the relief mechanism opening the choke valve in response to an intake vacuum pressure within the intake passage when the engine is in a cold state and the choke valve is in a fully closed state.