Mercury - Tachometer 7000 RPM SmartCraft Analog Gauge Black Face 85 mm 79-8M0052854. Overview. The Mercury Tachometer (79-8M0052854) gives you clear, accurate RPM readings so you can keep your engine running at its best. With a range up to 7000 RPM, it's ideal for most outboard and sterndrive applications. The black face, bright white numerals, and glass lens make it easy to read in all light conditions, and it fits a standard 85 mm (3-3/8") dash hole. Designed for SmartCraft-capable systems, th