ACC-RNGFR-PL-12 Yama ringless fuel additive improves power and efficiency in two- and four-stroke engines. Removes and prevents carbon and varnish deposits from injectors, carburetors, intake valves, intake ports and combustion chambers. These deposits are caused by poor fuel quality. It even combats the corrosive elements of sulfur in ethanol-blended fuels. Use with Yama Lube PLUS Fuel Stabilizer and Conditioner to avoid any harmful effects.