1963 Johnson V75 V4AL15E Voltage regulator

[EdsBoat]

I have a negative reading at the ammeter. I checked the stator and diodes with a ohm meter and check out OK. Ammeter checks OK. When I ground out the field terminal on the regulator the reading dose not change, it still shows a negative reading? Can I assume its a bad regulator?

 

[boobie]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

First check the 20 amp fuse on the junction box where the red bat cable attaches to. If that's okay, grounding out the field and it charges indicates a bad regulator.

 

[EdsBoat]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

I should have added I checked the fuse and its ok. When I ground the regulator the ammeter dose not change.

 

[F_R]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Wrong Fuse!! You should check the 60 amp fuse. It doesn't look like a fuse, so is easy to overlook. It is the assembly with a screw tab where the brown wires attach to the positive diodes heat sink. It is a ceramic affair with two thin metal fuse strips on the sides. If the fuse strips are melted, well there you go....

 

[boobie]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Thanks for the correction F_R . I knew what it looked like but I guess today when you say "fuse" not everybody knows what were're talking about. I used to put those on my old cars that had generators and regulators on them. That way they would blow if the cut out relay would stick in the regulator and you wouldn't burn up the generator.

 

[EdsBoat]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

OK, I checked the 60 amp fuse, the 20 amp fuse. Checked the stator with an OHM meter, OK, the diodes with an OHM meter, OK. The ammeter works. The battery is fully charged and new. All that is hooked up is the two battery cables, no accessories. The ammeter shows a negative draw of 4amps when running, when I ground out the field terminal on the voltage regulator nothing happens. It still shows a negative 4amp draw. According to the service manual when I ground out the voltage regulator it should show a change to negative or to positive. nothing happens. That's my problem? What is next? Replace the voltage regulator for the second time?

 

[boobie]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Is the ampmeter wired correctly with the boat/mtr wiring harness?? Mayde F_R will chime in if he has a wiring diagram. I don't.

 

[EdsBoat]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Yes, Its wired correctly. I had the boat out and ran for about two hours when it started not to charge. The ammeter showed charge for about 1 1/2 hours then a negative charge. I had a NOS voltage regulator and changed it, no change. I also have a NOS stator, Diodes ETC. What would be the item that would cause this before I change everything?

 

[F_R]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Don't guess, test. You sound like you have the service manual.

With the key on and motor not running, you should have 12V at stator's red wire and 0V at the stator's blue wire (because it is grounded through the regulator). BTW, if grounding the regulator's field terminal doesnt make it charge, it is not a bad regulator.

Personally, I have never seen a bad stator, but I suppose all things are possible on a 48 year old motor.

I suspect a broken wire, a bad diode, or the 60 amp fuse. You say you have tested them all. What else can I say?

Test everything.

 

[EdsBoat]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Well! I don't have a wiring diagram. How should the Diodes be wired up? Two connect to a jumper. Should they be + to + or + to -, ?

 

[EdsBoat]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

F_R ,my service manual dose not show the wiring diagram of the diodes. Where could I get one? ED

 

[F_R]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

There are four diodes, two negative diodes screwed into the junction box, and two positive diodes screwed into the heat sink. I think they have to be disconnected to test.

You have a PM

 

[AdamBomb78]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

I'm new here and I know this is not my thread, but I'm having the same problem that Ed is having and have tested everything above exept the diodes.

My quesion is about the 60 amp fuse, I have found mine but I'm kinda confused about what is should look like. Are the little tabs sapose to connect to something or should it look like this.

I did stick a voltmeter on the + diodes while running at got about 16 something volts, so I'm charging, but its not getting to my battery. Thanks

 

[boobie]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

That fuse is blown. Get a new one.

 

[F_R]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

That fuse is toast. If fact, half of it is missing. As a temporary test, connect the wires directly to the positive heat sink and see if it charges. Part number 378456, replaced by 379788. marineengine.com has them in stock.

 

[AdamBomb78]

Re: 1963 Johnson V75 V4AL15E Voltage regulator

Thanks a lot for the quick responses, you guys are great.