Zep CARB-X Carburetor & Throttle Body System Cleaner is designed for gasoline engines to help dissolve and flush away gum, varnish, carbon, and grease from carburetors, throttle bodies, induction systems, and related components. The formula is designed for use on carburetors, automatic chokes, PCV valves, throttle plates, and idle air control systems. It contains no chlorinated solvents, lead, silicone, or phosphorus and is formulated to not harm oxygen sensors.