tach wiring

[rockytop93]

can anyone tell me where on a 75 merc 650 65 hp to hook up the tach lead? the original control assembly is missing, but do have original wiring harness. What color wire in the harness goes to the pul terminal on the tach? Also, what pulse setting for a three cyl enginge? Thanks

 

[morge]

Re: tach wiring

Did you ever find out what you needed? I am wondering how to hook up the VDO tach to my Merc 650. There are three wire out of a small harness off the front of the control box - green, white, and black. I get 12V reading across green to black and 13V ocross white to black. I am hoping the green is the tach feed. Next question is what pin to use on the back of the tach - 2,3, or 4?