If your engine isnt performing like it should, it could be because of performance-robbing build-up in the combustion chambers. Restoring lost power is easy with Mercury Power Tune Internal Engine Cleaner 858080K03. Available in a convenient spray formula, Power Tune helps break down and remove carbon, gum and varnish deposits that are the result of normal engine use, especially in low temperatures or with some fuels. Removing these deposits improves fuel and air flow to help enhance overall engine performance. Its safe to use in all two-stroke and 4-stroke carbureted and fuel-injected gasoline engines, as well as catalyzed engines.