Sta-Bil Start Your Engines! Fuel System Revitalizer. Designed to ensure easy starting of small utility and recreational engines (2 & 4 cycle motors). Revitalizes fuel and the entire fuel system. Ensures smooth idling and performance. Helps remove gum and varnish from throttle plate and carburetor. Can be used anytime an engine begins to run rough or becomes difficult to start, especially after long-term storage. To use, simply add to the equipment's fuel tank. Will not harm gasoline engines. Not recommended for diesel engines and may cause severe damage. Good for 2 years from date of purchase, provided the product is tightly capped and stored in a cool, dry place. 2 oz.