Installing Tach on 01 50hp Merc

[reelhappy]

Hello All,
I am mounting my 2001 50 hp Merc on a new boat and decided to install a Tach so I can prop it correctly. I have the harness that plugs into the controls and the wiring color code chart I know the grey is the Tach wire the black is the ground but on the chart is says the purple is the instrument feeds. I would like to know if by this they mean that this is a hot wire when the key is on. The gauge says ignition so I am assuming this is the wire for that terminal. There are a couple other wires in that harness but I believe these are not needed for the tach. Any info would be appreciated.

Thanks

 

[Silvertip]

Re: Installing Tach on 01 50hp Merc

That wire must have +12V on it with the key on. That wire can connect to the +12V terminal on the fuel gauge or voltmeter if you have one. Otherwise, turn the key on and use a test light or meter to check the wires in the harness to see which one is hot. Then turn the key off to make sure that wire actually turns off when the key is off. Don't forget to set the calibration dial on the back of the tach before you button things up.

 

[fishingdan]

Re: Installing Tach on 01 50hp Merc

Yes, the purple wire is for key controlled instrument 12v power.