Tach Senders

[dirtyoldman]

Can anyone tell me what the two wires going to the tach are> This is on a 1968 Mercruiser 160. I need to diagnose a non functioning tach.

 

[Uraijit]

Re: Tach Senders

One will be 12v power, the other will go to the negative terminal on the coil.

 

[Uraijit]

Re: Tach Senders

Oh, and a nice way to test a tach is to connect it to a 12V battery charger.

If the tach is working, you should get a reading as follows:
* 1800 rpm for an 8 cylinder,
* 2400 for a 6 cylinder
* 3600 for a 4 cylinder