Troubleshoot tach setup help.

Good day,

Could appreciate a bit of advice.

Setting up a tack on my Evinrude 70773S motor.

I’m using the Evinrude tach cable that connects into the control box.

I thought things would be simple but as usual they are not.

Wires from the cable are connected correctly to the tack and plugged into the control box but nothing is happening.

Because the cable is a bit old I checked each prong of the tack cable and there is continuity from one end to the other.

I then opens up the control box and plugged the cable in and there is connectivity from the tach to where the black, grey and purple cable originate in the control box.

So my questions.

1. With the motor running what should the voltage be across the black and purple cable in the control box? I am assuming it has to be greater then zero.

2. Is there a way to check that the grey wire in the control box is providing a tach signal?

Any other troubleshooting suggestions?

Appreciate the help.

Alex


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Bump for visibility.


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Purple in OMC world means "Switched 12V power", so w/ the switch ON but motor not started, it would be close to your battery voltage, e.g., hopefully at least 12.6 volts. And it would rise to correspond to the charging value (if equippped) that is typically 14+ volts.

Can you adjust the settings on the back of that tach, from 1 to 6 poles or 1P to 6P or such? Or from 2, 4, 6 and 8? Tach connections could be 'dirty', where the Teleflex FAQ page used to tell one to turn the pole setting between settings to help 'clean' any corrosion of the contacts.

Usually a tach NEVER reads 0 RPMs when the ignition is OFF, as it floats/sits somewhere higher, but if the tach does not read 0 when the ignition switch is turned ON, that is usually bad. A bad rectifier can also cause a tach not to read. So if you don't see higher voltages at higher throttle, that might be where to look. But I'd advise at that point to buy one of the online factory OEM (like OMC or Bombardier) service manuals 1st and not a Clymer or Seloc engine service manual. Friends don't friends buy Clymer or Seloc engine repair manuals!

What year and HP? That old # means nothing to me. Electric start? Do you know if it ever successfully charged a battery?

Hi

It is a 1977 75hp Evinrude 3 cylinder.

So I can see about 12v at the control box.

When I hooked up the accessory cable and checked the voltage at the cable ends I got zero volts.

So I checked connectivity between the accessory cable ends and the 12v and ground points in the control box and there was zero connectivity.

So while the control box and cable are independently fine together they are not.

Looks like the accessory cable is not making a good connection at the accessory plug.

I’ll try to clean the connection points and try again.

Appreciate the guidance.


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Hi

The cable was rotted. I made a new one and things are much better.

Now I need to know how to configure the tach.

Please see the back of the tach. I bought this tach a while ago and I have misplaced the instructions n

And this is for a 3 cylinder motor.

Any suggestion on the right setting.






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