JPS57198350A - Starting system of carburetor - Google Patents

Abstract

PURPOSE:To obtain a rich starting mixture, by introducing the atmospheric air pressure to the upper chamber in a carburetor float chamber through an atmosphere introducing passage, fetching positive pressure in a crank chamber through a positive pressure introducing pipe, providing said positive pressure introducing pipe, providing said positive pressure introducing pipe branching from said atmosphere introducing passage and feeding said positive pressure to a liquid level of fuel when an engine is started. CONSTITUTION:A supply pressure selector valve main unit 18 comprises an atmosphere chamber 19 and positive pressure chamber 20, and the positive pressure chamber 20 is equipped with a positive pressure introducing passage 24, communicated to a crank chamber, and a selector valve unit 27. At starting, an operating rod 27A is lifted to close a communication passage 21 and open the positive pressure introducing passage 24. In this way, an upper chamber 5A above a liquid level is communicated to the positive pressure introducing passage 24, and positive pressure is applied into the liquid level upper chamber 5A. Accordingly, sucked fuel into an intake pipe 2, from a main nozzle 10 and each hole 13, 14, can be increased, resulting in the supply of a rich mixture. After warming up of an engine, if the selector valve unit 27 is moved downward, the liquid level upper chamber 5A is opened to the atmosphere.