Mercury - SC1000 Tachometer 5000 RPM (No Logo) SmartCraft Analog Gauge Black Face 85 mm 79-8M0135657. Overview. The Mercury SC1000 5000 RPM Tachometer (79-8M0135657) gives you smooth, accurate engine readings with a simple, no-logo look. The black face and white markings are easy to read, and the glass lens keeps it clear season after season. It drops right into a standard 85 mm (3-3/8 in.) dash hole and ties into your SmartCraft network for true engine data. It's clean, tough, and made to last