SU carburetors (named for Skinners Union , the company which produced them) were a brand of carburetor widely used in British automobiles for much of the twentieth century. Originally designed by George Skinner in 1910, they remained in production through to the 1970s.
SU carburetors featured a variable venturi controlled by a piston. This piston has a metering rod that closes the passage of fuel, so the movement of the piston is converted into getting the correct proportion of fuel.
