I have a 2001 Honda 50 hp. tiller. It also has a remote key switch. I want to hook up a tach and a water pressure gauge. The old motor was a merc 2 stroke and had a water pressure gauge that goes to 15 pounds. I don't know if this gauge will work for me and I don't know how or where to hook it up to. I will buy a new Honda water pressure gauge if needed. I bought a new Honda tach but there were no instructions on how to hook it up either. The old tach for the merc has 4wires and the new Honda tach has 5. I don't have a wiring diagram and don't know where all the wires go. Hope you can help. O-R Thanks

The 50 does not have a water pressure port on engine to connect water pressure gauge hose, you might can install a Tee fitting in tell-tale hose and connect pressure hose to Tee.
You need to get the gauge harness to match the tachometer(Honda offers many differtent name brand gauges) you bought to connect tach to key switch.

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