Review on 🚗 ITYAGUY Waterproof AUTO Digital Tachometer Tacho Gauge - 6000 RPM, Red Backlight, 85mm, 9-32V - Ideal for Car, Boat, Motorcycle by Alfonso Alexander

For mounting on Mercruiser 3.0L outboard motor. As others have said, there is no wiring harness. However, the connection is made via standard size connectors. With the engine idling, it took about 15 seconds for the needle to start registering pulses. The needle was stuck in the idle position even when the engine was throttled up or down through the carburetor. Connection. It looks like the unit's low pass filter is too aggressive and has a high dB rolloff at low frequencies. I will try another transmitter or signal generator to verify functionality before sending back.