PURPOSE: To prevent icing and vapour lock in a carburetor by connecting the carburetor to an engine high temperature part through a heat transfer member, and providing a thermal clutch to intercept heat transfer at high temperature in the said heat transfer member.

CONSTITUTION: Mixture is supplied from a carburetor 2 to an engine 1 through a suction pipe 1b. In a high temperature part of the engine 1 and the carburetor 2, heat generated in the engine 1 is transferred to the carburetor 2 through a metal rod 3 stretching from the engine 1, a heat transfer member 8, and a metal rod 5 stretching from a heated part of the carburetor 2 to prevent icing there. The heat transfer member 8 is pressed against a spring 9 by an actuating member 7a which is protruded against a spring 7b by a thermowax 7 to expand according to the temperature of the metal rod 5 stretching from the carburetor 2, and when the carburetor is at high temperature, the heat transfer member 8 separates from the metal rod 3, resulting in no heat transfer from the engine 1 to the carburetor 2. Thus, vapour lock can be prevented.