Carburettor with cold start system - has opposed bimetallic and modulator springs acting on three arm lever coupled to regular shaft which is connected to choke flap

摘要

The carburettor has a single choke flap fitted eccentrically to a shaft. The mixture flow is regulated by twin throttle flaps fixed to a common shaft. The choke flap (30) is coupled to a regulator shaft (44) joined to a three armed lever working with a bi-metal spring. The latter allows the choke flap to open fully in reaching normal working temperature. The bi-metal spring (68) works against the force of a modulator spring (76) fixed to the second arm (78) of the three armed lever. The modulator spring force overcomes that of the bi-metal spring between temperatures of 15-38 deg.C. The third arm (84) rests against an adjustable stop (82). A cold slow running cam (86) pivoting on a shaft (88) has an arm (90) which is mechanically coupled to a part of the regulator shaft (44).