Highly concentrated Yamalube Ring Free PLUS is a proven engine deposit cleaning package. When used as directed, this top-quality deposit-control system removes deposits from fuel injectors, carburetors, intake valves, intake ports, and combustion chambers. These harmful deposits, often the result of low quality gasoline, may cause knocking/pinging, power loss, hesitation, shortened spark plug life, piston ring sticking, and even expensive engine damage.