How to Wire Up my NEW TACH

[wishboneZ51]

Ok everybody I was looking for posts about how to install my tach with no luck.

I am putting my new to me motor on my boat and installing the steering wheel kit. So I purchased a tach which is made by Mercury, quite expensive might I add. Anyway, even with the instructions I am not following how to install it. I have my manual and it does not have any info how to do it either.

I have a 1974 50HP Johnson which is a 2 cylinder
8000 Merc tach for most electric start outboards,sterndrives and inboards. Designed for 4-6-,or 8 cylinder standard ignition or outboards equipped with a 12-pole alternator.

Please help?

 

[Silvertip]

Re: How to Wire Up my NEW TACH

So what has you puzzled. The tach needs +12 volts when the key is ON. It also needs ground. It then needs the SENDER signal from the charging system. As for settings, it needs to be set to the 6P (6 pulse-12 pole) setting. Verify the connections and settings. The tach normally has an "I" (ignition) terminal which is the +12 volt connection with key on. Ground is -- well -- ground (negative terminal of the battery), the ground terminal on any other gauge, or a ground terminal on the ground buss. The sender connection is to the tach wire in the engine harness going to the throttle/shift control box. If that wire isn't there, you need to run one back to the engine and you need the wiring diagram to determine where to connect it. Those engines have a terminal strip on the starboard side of the engine to which the charging system connections are made.