HOW THE MIXTURE THROTTLE VALVE WORKS IN KZ KARTS

In karts with a float carburettor and relative petrol pump [A], the “standard” operation is as follows. The piston in the engine moves down and in so doing pushes petrol from the pump to the carburetor. Each time this happens, some of the petrol is sent from the pump to the carburetor [A1], while the quantity in excess of that needed for setting the carburetor is carried, through another tube, towards the tank [A2], so as to become usable in subsequent engine operating cycles. [B] When the valve is introduced, [B1] mounted on the section of the tube that carries the mixture back to the tank, this, if “closed”, allows the flow to be reduced. Following this choking, an increase in fuel pressure is generated on the petrol inlet housing in the carburetor, triggering a rise in the level inside the tank, causing a consequent forced enrichment of the carburetion. By turning the valve, it is therefore possible to precisely change the fuel level in the carburetor bowl, modifying the carburation in a timely and controlled manner. [C] By turning clockwise, the throttling is increased and consequently the carburetion is enriched. Turning counter-clockwise, of course, returns to the original carburetion setting, which is "leaner".