To provide a device preventing unprepared motion of a fuel flow calibration setting needle.
A body of a rotary throttle valve type carburetor includes a throttle chamber communicating to a air fuel mixing passage and an air fuel mixing passage, and a fuel flow passage. A throttle valve is stored in the chamber movably in a rotation and an axial direction, and moves between an idling position and an expansion open position to control air fuel mixture flow in the mixing passage. An insertion valve threadedly inserted in and retained by the carburetor adjusts flow rate of fuel from the carburetor through the fuel flow passage. The insertion valve is rotated and moved in an axial direction along the thread by a tool engagement part of the insertion valve. The tool engagement part is not in a round shape and mates with just a special tool. The insertion valve is retained by the throttle valve and moves together with the same. The tool engagement part has a flat surface and is in a roughly D-shape. A carburetor body includes a recess in which the tool engagement part is arranged to limit entrance to the tool engagement part.
OGASAWARA HIROKI
TAKAHASHI TETSUYA
TAKAHASHI TOSHIMASA
VIMERCATI GIOVANNI
Hiroshi Ochi
Fumio Takino