Tach problems - completely lost

[Sbassin22]

I've had an old boat for a few years. None of the gauges work. I always assumed it was because the previous owner repowered it and messed up with wiring somehow. I just drove it the way it was because it worked fine. Problem now is I have been needing to mess with props because of the weight I added with a talon. Obviously need a tach to know what's going on.

So I bought a mercury tach hoping that I would somehow get lucky and it's just a bad tach that came with the boat. Wired it up, made sure I had the pole setting right at 6P, started it up and nothing. In order to eliminate any issued with the wiring harness or any wires that could possibly be an issue but buried somewhere I decided to run a separate sending wire myself directly from the tach to the sending wire coming out of the voltage regulator. Still nothing. Tried running the wire to the sending wire coming out of the other voltage regulator and still nothing.

I then tried a test light on both gray wires while idling and it did not come on. I don't have a multimeter and even if I did I don't know how to read them, but a tach seems so simple. What am I missing?

93 black max 175 0g001185

I of course searched and googled, and it sounds like both my voltage regulators could be bad? What do you think?

[JOE54]

regs very possible

[silverbullet02]

Do you have power and good ground to the tach?

[Sbassin22]

Do you have power and good ground to the tach?

Yes sir.

[Rip Bass]

To add to Joe54’s post,if the regulators are fried,the tach won’t work. Look at the connectors on the wires coming from the regulators to see if they are burnt looking,sometimes you can smell of the regulators to see if they smell burned.

[EuropeanAM]

And if there is any evidence of burnt spots, browned/blackened or burnt connectors... replace BOTH regulators using only OEM units (no aftermarket).

[Sbassin22]

Thanks all. I replaced both regs and now the tach is working. A couple of the connections on both of them were slightly brown/burnt looking. Another problem solved by the BBC.

[JOE54]

ROLL ON