Free wiring diagram wiring diagram for a boat tachometer images hp johnson outboard mercury. Tachometer wiring you need continuity or lack there of on both posts. Faria Kronos 4" Tachometer 7,000 RPM (Gas All Diagram a vdo tachometer with hourmeter is programmable from.5 to 200 pulses per revolution vdo vdo item description quantity 1. Boat tachometer wiring diagram . Make sure this switch is set to the number of cylinders for your engine. Wiring diagram comes with several easy to adhere to wiring diagram guidelines. At the top left of the diagram, we see the cylinder selector switch. This way, even if your battery switch is off, if your boat starts filling with water the pump will still kick on. It’s pretty standard in boat wiring to bypass the main battery switch for one thing: I think things like speedos, trim tilt angles that kind of thing is a bit marginal but a tachometer is a really useful thing. Always disconnect the battery ground before making any e...