teleflex tach and 1975 8500?

[tompowers85]

I just bought a new teleflex tach for my 1975 85hp merc, and i cannot get the tach to work. I tested the sending wire and i have 4 ac volts, but it will not show on my guage. I have power on the (+). Does it sound like i have a defective tach, or do those guages not work with that motor.

 

[Chris1956]

Re: teleflex tach and 1975 8500?

Tomp, Do you have a good ground on that tach?<br /><br />Those Tachs work off the stator coil. They count the pulses to determine RPM. Make sure it is connected to 12V + Battery voltage, ground and one of the stator wires of the charging system. make sure the Tach is set to 12pole setting.

 

[tompowers85]

Re: teleflex tach and 1975 8500?

can i connect it straight to one of the stater wires or are the voltes to high.

 

[Clams Canino]

Re: teleflex tach and 1975 8500?

You can go direct. Also you can move the old tach lead in the harness the controller from the switchbox to the stator lead where it meets the rectifier. then you can wire it up "normally".<br /><br />You can't use a new tach with the switchbox pickoff.<br /><br />-W

 

[tompowers85]

Re: teleflex tach and 1975 8500?

Thanks i am going to try that.