I am installing an aftermarket Teleflex tachometer on a 2000 40hp Yamaha. The wiring harness out of the control box has a power (red) wire that appears to be continuosly hot, regardless of the ignition switch position. Should I use this wire for the power to the tach (it is bundled with the green/send and black/ground wires)or go inside the control box and attach to the ignition switch. My concern is how much power draw to the tach and danger of draining the battery during periods of non use. I don't have a battery switch on this boat and would have to disconnect the battery if power draw is a concern. Anybody know how much amperage draw is involved with a tachometer when the engine is not running?
