Patent ID: 6619632
Filing Date: 2003-09-16
Classification: F02M

Abstract:
A choke valve device in a carburetor including a carburetor body having an intake passage, comprising:a choke valve opening and closing said intake passage at a location upstream of said intake passage; a valve stem attached to said choke valve and rotatably carried in said intake passage; a spring biasing said choke valve in an opening direction; a negative pressure operating chamber provided in said carburetor body to communicate with said intake passage at a location downstream from said choke valve; a locking piston mounted in said carburetor body with its pressure-receiving face facing said negative pressure operating chamber and adapted to be advanced and retracted between a locked position (L) and an unlocked position (U), said locking piston being biased toward the locked position (L) by a locking spring; and a choke lever secured to said valve stem provided with a locking portion which restrains said choke lever at the fully closed position in such a manner that said locking portion engages with said locking piston advanced to said locked position (L) by a biasing force of said locking spring when said choke lever has been moved to a fully closed position (C) of said choke valve, wherein said locking piston is retracted to said unlocked position (L) and is disengaged from said locking portion when an intake negative pressure equal to or greater than a predetermined value is introduced into said negative pressure operating chamber upon starting the engine.