Connecting Old Tach to New Mercury Control

[imported_Rycher]

I have an OLD tach built into my center console. I put a different motor and controller on boat last year and want to connect up the old tach to the new control. The tach only has 2 wires coming out of back, Black and Green. Im assuming i connect it up to the harness coming out of the control (Pic Included). Is there a wiring harness that will connect to the black rubber connection coming out of control.. its 4 pin (Black, Grey, Purple, and white w/ blue stripe, also a Tan color wire hanging to the side) So i guess i have 2 questions. Is there a harness i can buy to connect to rubber connection and just solder wires coming from tach to that. or if i hard wire it, where do the Black and Green wires connect to? .. I know one is a signal wire but not sure what other wire out of tach is used for.. power/ground?

thanks for any help

 

[Chris1956]

What year is the new motor? That tach may only be compatible with Mercs using battery powered CDI ignitions. They were D/C on 4 cylinder mercs in 1976 and 6 cylinder mercs in 1979 1/2.

 

[imported_Rycher]

Thanks for the reply.. this is a 1985 60hp mercury 3 cylinder.

 

[Chris1956]

I believe you will need a newer universal outboard (3 wire) tach for your motor. These are powered by +12VDC, ground and the pulses from one of your rectifier AC post.