Tachometer Question

[Plank]

Own a 1974 85hp Merc. Would like to install a tachometer, do not know much about it. Will any tach work, or do i need a Merc tachometer? Lots of good deals on e-bay if they will work on my engine. Thanks in advance for all your help.

 

[petryshyn]

Re: Tachometer Question

There are tach available that connect to your charging system.(alternator tach) Teleflex and faria make em. Lots on e-bay...<br /><br />click me<br />

 

[skier]

Re: Tachometer Question

Most any tach will work with your motor. What you need to do first is look at your control box. In the front of the box near the bottom there should be a plugin. If yours has the plug then it's a no brainer. Go to a parts place that has Mercury parts and get the tach harness. It should have directions with it. There are three wires in this harness, if the control box has the plug your already pre-wired for a tach.The tach should also have directions to tell you what wire goes where. My boat is not close by to let you know for sure what wire goes to what terminal.<br /><br />Hope this helps and happy boating

 

[Jumper]

Re: Tachometer Question

Going thru and reading up on Tachs since I need to get mine running and came across this. I've got a 73 Merc 850 and my tach's not working. However, I have three wires that are just hanging loose under the steering console. Not sure exactly what the colors are off the top of my head (I'm at work) but I have the plug in the front of the control box that Merc is talking about. Is it possible the three wires hanging loose (without the plug) are the wires for the tach? If so, what color should/could they be? I'm getting some sort of power to my tach since the backlighting is coming on, but it's not reading the RPM's like it's supposed to. Where could I find a plug to rewire these three rascals if in fact they go to the tach? (Sorry guys, I haven't really paid to much attention to where they run under the console which is why I'm asking) I do know one of them appears to be a ground wire.

 

[taz33911]

Re: Tachometer Question

I could be wrong but I think gray purple and black . The light is from probably a blue wire from another gauge they run in series.

 

[Jumper]

Re: Tachometer Question

Thanks for the reply taz. When I got home from work the other day, I noticed the wires were orange and black (the wires for the horn). I ended up just running a wire straight from my tach to the rectifier on the motor (see "Need Tach clarification for 73 Merc 850"). Thanks again for the reply!!