So I took my new to me 77 Tarva with a 460 ford out to Blythe to drop into the water and see if everything was water right and to finish doing some trailer work while the boat was off.
She's water right and the jet seems good but my voltage meter on the dash never went over 10. So as much as I wanted to get down the river ,I never left the cove.
I pulled the alt and it was a 37 amp Motorola. Had it tested and was told it was dead. Got a replacement 1 wire marine alternator fired it off and I'm still showing 10 amps on my dash meter. But my tester is showing 12 on the battery.
If my battery is showing 12 shouldn't my dash meter be reading 12 too?



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You're all over they place here.

What gauge do you have?  An ammeter or a volt meter.

If the boat originally had an amp gauge, there are going to be two wires going to the dash, should be an orange and a red.

These wires carry the charge from the alternator to the dash and back.

With a one wire alternator,  you talky need to go from the alternator straight to the positive post on the starter solenoid.  You will then need to tie the Orange and red wires together.

It sounds like either the volt gauge is defective,  or the voltage drop at the dash is extreme... Either that or it's an amp gauge, still defective.

The drawback to the single wires ate they don't reference the drop to the dash, so typically they tend to under charge. ...


Good luck bud.

GT


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Just a shot in the dark...I wonder if it was originally wired for an amp meter and the harness wasn't converted for a volt meter

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In the morning I'll test what colts are getting to the meter gauge itself. 


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That wiring is a mess.

Where does the large wire from the alternator go?

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That wiring is a mess.

Where does the large wire from the alternator go?

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So it was tighter before I clipped the ties holding them and removed the cover for the wires so I can see where things go.

The wire from the alternator goes to the starter solenoid then back to one of those white plastic square that has a reset button on it. Still trying to figure out what they are.
I've wired up a chopper before but that was pretty basic. Is there a better way to wire up this meter. I'll run new wires just for that if there is.


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So it was tighter before I clipped the ties holding them and removed the cover for the wires so I can see where things go.

The wire from the alternator goes to the starter solenoid then back to one of those white plastic square that has a reset button on it. Still trying to figure out what they are.
I've wired up a chopper before but that was pretty basic. Is there a better way to wire up this meter. I'll run new wires just for that if there is.


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Those are circuit breakers and should be "closed" unless tripped.

Someone did some heavy duty electrical work that in my personal opinion needs to be redone.

You had 15 volts at the alternator, but 12 at the start solenoid. That speaks bad wire or connection between the post on the alternator and the solenoid.

Using an ohmeter with the battery disconnected, check the continuity from the alternator to all those red wires, they should all be directly connected and the resistance should be no more than an ohm above meter resistance.

My personal feelings is you should be able to eliminate quite a lot of that Bird nest material. Ideally, you should have 14.5 volts everywhere except the ignition coil with the engine running.

Good hunting.

GT

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Also wanted to say thanks for the help.


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More info and questions.
So my old alternator was a Motorola that had 1 wire to the starter solenoid and 2 wires together attached on a different plug. The purple wire and a smaller red wire that went to the distributor. I was told to just tape off those wires cause I won't need them. Bad information?


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I prefer to "cut them back" but isolating works too.

GT

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So I'll ask one more stupid question. 
Where should the dash voltmeter be reading from?
Battery, starter solenoid, or alternator ?

Thanks again for the help.


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In my 50 years on this planet, I have come to realize that the only stupid question there is, is one you answer yourself while asking. Meaning you didn't think it through.

That being said, it should come from the ignition switch "I" terminal which ultimately comes from the main power wire from the circuit breaker through the switch. Still should be very close to battery voltage minus the resistance of the 20+/- feet of wire.

GT

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