Mercury - Fuel Level 2 Gauge Black Face 2-1/8" (52 mm) 79-8M0052845. Overview. The Mercury Fuel Level 2 Gauge (79-8M0052845) gives you accurate fuel readings for a second tank or additional sender setup. With a black face, bold white markings, and a glass lens, it's easy to read and matches perfectly with other Mercury SC1000 or SmartCraft gauges. It fits a standard 2-1/8" (52 mm) dash opening and works with SmartCraft-capable systems when compatible sensors are installed.. Key Features. Fuel Le