Marver Mystery Oil, Pint, Cleans and lubricates fuel injectors and carburetors. Improves gasoline mileage. Reduces and prevents varnish and gum build-up. Extends spark plug life. Safe for catalytic converters and oxygen sensors. - ADDED TO ENGINE OIL: Prevents valve sticking and clatter. Fortifies properties of engine oil, prevents breakdown caused by extreme temperatures. Promotes easier cold weather starts. Reduces and prevents acid and sludge formation. For all Marine Engines.