Install Tach 1975 85hp

[68ltdwagon]

I have a 1975 85HP Merc 4cyl in which I would like to install a tach. Can i just connect the sender wire right into one of three terminals on the front of the control box? Do I need to get a certain type of tach? does it need to be a 12 pole? not sure what that means but ave seen it a lot when looking at tachs. Or does it just need to accept a 4cyl outboard.

 

[Barnacle_Bill]

Re: Install Tach 1975 85hp

The connector on front of the control is for the tach. It has 3 wires, black-ground, white-power, and brown-tach. Not sure how many poles you need, but any good tach is switchable.

 

[68ltdwagon]

Re: Install Tach 1975 85hp

How can I tell what tach I can use. What do you mean by switchable? Does anyone know what they are talking about when they are referring to poles? Is my merc a 12 pole? Can I just use the 4cyl setting on the tach if I use the wires in the in the connector?

 

[Barnacle_Bill]

Re: Install Tach 1975 85hp

They are refering to the number of poles in your stator. Switchable means it can be switched to match the number of poles.

 

[68ltdwagon]

Re: Install Tach 1975 85hp

Does anyone know how any poles are in the stator on a 1975 85hp 4cyl?

 

[Ben Konopacky]

Re: Install Tach 1975 85hp

hi 68; yours should be set at 12 pole/6 pr..if you are not using a merc tach. you will need the 3 prong adapter to use the plug on the control .I like my teleflex.for some reason wasn't geting a sig.from the brown wire at sw.box so i moved it to one of the alt.yellow wires and its ok since.