How to wire tach to engine

I have a Suzuki NSA 2177 Tach with a Gray, Yellow, Black and a red wire coming from it. I have a 40HP Mercury # OD163044 outboard that I want to use this on.
Where do I connect the Tach wires to ? Any help would be greatly appreciated.
Thanks, Tony

Re: How to wire tach to engine

Tough question tony, If it were a mercury tach you would go red to switched positive, black to ground and the gray is the sender wire from the rectifier but that still leaves the yellow. do you have a wiring diagram fot the tach or suzuki engine that it is suppost to before? we don't even know if the 2 are compatable as alternator have differant number poles (pulses)

Re: How to wire tach to engine

I do not have a wiring diagram. the tach was hooked up to 1984 Merc 30HP before and worked fine.
Tony

Laddies said:

Tough question tony, If it were a mercury tach you would go red to switched positive, black to ground and the gray is the sender wire from the rectifier but that still leaves the yellow. do you have a wiring diagram fot the tach or suzuki engine that it is suppost to before? we don't even know if the 2 are compatable as alternator have differant number poles (pulses)

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Re: How to wire tach to engine

I do not have a wiring diagram. The tach was working fine before on this boat with a 1984 30HP Merc. I replaced the 30 with this later model 40 and am not sure where to hook the wires to. On the 30 the red & gray wire were joined together and attached to a purple wire and all the black leads were spliced together. I think the yellow was spliced to a tan or white wire but the 30hp was two cylinder and had no electronics.

Re: How to wire tach to engine

Beats me I have never worked on a Suzuki

Re: How to wire tach to engine

Gray key switch 12v
Yellow tach
Black ground
red is stop engine

ask brownspoint.com

Re: How to wire tach to engine

JUSTINTIME said:

Gray key switch 12v
Yellow tach
Black ground
red is stop engine

ask brownspoint.com

Click to expand...

Re: How to wire tach to engine

i have determined that the red wire is for the light and the black is the ground. what I need to know is where the yellow and gray wires attach to. If anyone can help it would be very much appreciated. The motor is a 40 hp Merc and the tach is a Suziki.
Thanks in advance, Tony

Re: How to wire tach to engine

We seem to have a variety of choices and depending on the boat and who wired it, colors may not be applicable (in the boat). I seriously doubt that the red wire is the light. Red is almost universally used as a +12V. That said, if Suzuki followed the wire color code, the gray wire is the tach feed. If you have a short wire harness coming out the back of your Mercury control box, the tach feed is in that connector and is also a gray wire. Red is +12V and that can be connected to the +12V terminal on the fuel gauge, temp gauge, trim gauge, or voltmeter if you have one. That line needs to turn on and off with the key. Black is ground. Connect it to the ground terminal on any other gauge. I'm guessing that yellow is the light. Verify this by removing the bulb and then using an ohmeter, measure between the yellow and black wire. If it reads open, that's the light. If you get any other reading, it is not. If it's the light, connect that wire to the light terminal on any other gauge or to the same terminal you connected the red wire to. That means the light will be on any time the key is on.