Carburetors for internal combustion engines

Claim 1

Carburettor for an internal combustion engine, comprising: an intake pipe; an operator actuatable main throttle member in said pipe; a main fuel jetting system which opens into said pipe upstream of said throttle member for providing fuel to the engine during operation thereof under load; and an auxiliary cold starting device responsive to the temperature of the engine to increase at least the flow rate of fuel delivered to the intake pipe, said auxiliary device including a passage which opens into said intake pipe downstream of the main fuel jetting system, a closure valve in said passage, means for delivering an air fuel mixture of predetermined richness to said passage upstream of said closure valve, first temperature responsive means for closing said closure valve when heated to a first predetermined temperature, a starting choke valve located in said intake pipe upstream of the main jetting system, and second temperature responsive valve actuating means for moving said starting choke valve from a minimum opening to a more broadly open position when heated to a second predetermined temperature, wherein said temperature responsive means are constructed and arranged for the choke valve to be moved from its minimum opening position before the closure valve is closed following starting of the engine.