the throttle valves having mushroom-shaped bodies

Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type; Carburettors having fuel-air mixing chambers of variable shape or position > having other specific means for controlling the passage, or for varying cross-sectional area, of fuel-air mixing chambers > Axially movable throttle valves concentric with the axis of the mixture passage > the throttle valves having mushroom-shaped bodies

Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type (register-type carburettors F02M11/00); Carburettors having fuel-air mixing chambers of variable shape or position > having other specific means for controlling the passage, or for varying cross-sectional area, of fuel-air mixing chambers > Axially movable throttle valves concentric with the axis of the mixture passage > the throttle valves having mushroom-shaped bodies