| 摘要 |
PURPOSE:To prevent fuel from outflow in running an engine from an exhaust path of a suction type primer pump for applying negative pressure to a diaphragm chamber of a carbureter prior to start of an engine by interposing a valve closed during the running of the engine in said exhaust path. CONSTITUTION:A diaphragm type carbureter of a compact engine for a chain saw or the like comprises a fuel supply mechanism 24 provided with a fuel pump 18 and diaphragm chamber 22 formed on a portion of the peripheral wall with a diaphragm 20. Also, it comprises a suction type primer pump 64 for filling a diaphragm chamber 22 with fuel prion to the start of an engine. The primer pump 64 presses repetitively a semispherical elastic member 70 to discharge air sucked through a suction path 74b and a check valve 80 to the pump chamber 72 side through a check valve 82 and an exhaust path 74c and provide negative pressure in said chamber 22. The exhaust path path 74c communicates to a chamber 90 of a valve unit 84 closed by intake negative pressure during the running of the engine. |
