Need Help With Tach Installation

[Ol Sarge]

Hi, I'm new here and hoping for some help. I just bought a 93 Javelin 350A Bass Boat with a 92 70hp Johnson VJ70TLEND motor on it. I'd like to install a tach on the boat as it doesn't have any gauges at all on it now. I can't seem to find any info on the wiring to do the installation. I would appreciate any knowledgeable help I can get. Thanks in advance.

 

[sam am I]

Hi Ol Sarge,

Please see note on image below as you'll need to find the "gray wire" for the tach's (signal+) then a power and ground of course.

 

[Silvertip]

To make this as simple as possible, buy the harness that plugs into the receptacle just below the key on the throttle/shift control box. That receptacle provides +12 volts, ground, and signal from the gray (sense) wire. Easy-peasy! Otherwise, there is normally a stub cable with the same wires extending out of the control box. Those are specifically for gauges.

 

[Ol Sarge]

Thanks guys for the reply. I really appreciate the info. Can you tell me with a boat that is as old as this one is where I can get the harness from that plugs into the control box? There isn't a boat dealer or boat shop around where I live so pickings are pretty slim. If you can put onto a source that would be great. Thanks.

 

[BG0666]

Just did this last night I hooked up a rpm tach on my 80 Evinrude 70 horse. Ur purple wire that comes from the control box is Ur 12v aux wire only turns on with key next to that there is a pin hole wichw is gray u want that gray wire in control box.what I did was opened up the controller I went to the 3 pin plug found gray and sniped it at plug sliced back casing for wire harness so I can run gray wire out of control box.taped casing for harness back up jumped on the gray wire with my own right to gage and done

 

[Ol Sarge]

That sounds easy enough. Thanks for the info. I'll try and locate the pig tail from the controls and go from there.