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Onan 12 MDJC - 3r/2268d (1985)


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  #31  
Old 08-05-2017, 03:15:56 PM
MBB MBB is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Quote:
Originally Posted by Kevin K View Post
You need to verify the wiring diagram with your generator. The single spec letter in the model number indicates a Magneciter generator, so I limited my search to those models. Mike assumed it may be a later model using an electronic voltage regulator, and he may be correct. Check your generator to see if it has a YD generator end and electronic voltage regulator( newer model) or a Magneciter (older model).
Kevin I saw the age 1985 and figured it had to be a non Magneciter. An AD is viewed as a D. I also counted the items in the control box and they match the drawing I posted. Without getting answers its difficult to determine.
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  #32  
Old 08-05-2017, 03:35:13 PM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

It is a little hard to tell but it looks like a magneciter control box. The YD control boxes have 4 more wires coming up in the corner and going to the VR penthouse. The mag sets only have one wire going to the field flash connection on the mag terminal strip. I think the "1985" may be a red herring. A picture of the end of the generator would be helpful and definitive. Cheers Dan
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  #33  
Old 08-06-2017, 08:20:23 PM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Hi everyone, been busy keeping wife and daughter happy, so i was able to sit here now at the mall and log in, not my favorite place to be lol, any way not looking to close before, but it has i think 4 wires coming out of the genhead, i will verify when i get home, if,,,,,,lol, i dont know how to tell the difference between an exciter or the other kind, maybe some can explain, i am a mewwwwby at this, my first genset guys, be gentle, i will take some pics of the gen head so you can tell what i have, anyone else need some info????thanks again allof you,,,,much appreciated

Max, my box is a little fuller than ur pics , i have a heater solonoid also, question 4 u any everyone, those 2 tall resistores (i think) the one has wires coatings on both and other has one coated n 1 bare, what r they called on wire diagram n where do they go too? And i take it it has to remain a bare wire for a reason?, thanks

Yeah thats cool, i lve near steel lake park, rt next to it, what a small world,

Sorry that was responce to PnishrPW, and it was sold to me with a radiator small japanese or ?one with an electric fan, dont know if mechanical os better or not? I like mechanical, less fail parts, it was marine setup but changed to non marine, probanly will sell that marine stuff?
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  #34  
Old 08-06-2017, 08:38:08 PM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

If you open the wiring diaghram MBB posted in post # 21 above you will see

R11 and R12, those are the resisrors you are asking about, follow where the wires go in the diaghram.
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  #35  
Old 08-07-2017, 09:14:49 AM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

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Ok so I took some pics lasdt night and it has 4 big wires coming from the head to the breaker panel, one of them grounding, there also is a thinner wire coming from or going to the head thats a maybe 12 or 14 gauge wire? anyone know what and where it is supposed to connect to?
I attached the plate from a pic that has info on it about it being an ecxciter with #. someone please advise?

Thanks again
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  #36  
Old 08-07-2017, 09:26:35 AM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

sorry, the thinner wire is going to inside the control box .

alsao I have a wire that is in the box that starts from the emergency relay then terminal block and that wire goes to the sideof the motor not connected to anything, the end of it has a broken off brass connector like the oil pressure sensor and screw is still attached. where does this wire attach to or supposed to attach? Any and all feed back is very very much appreciated ...
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Old 08-07-2017, 04:20:26 PM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Ok so it is a magneciter machine, it was not made in 1985 but 1973 or earlier. A pic of where the two unknown wires come from and where they end up would be helpful to determining what they are supposed to connect to. Cheers Dan

The thinner wire coming from the head to inside the control box is likely the 12V automatic field flash lead. It should connect to the exciter terminal strip , I believe it is numbered 35 or 38 on the exciter. You should ohm out that wire from the terminal strip to inside the control box to be sure. It's purpose is to flash the field when the starter is engaged to ensure there is a good residual magnetic field to enable the generator to start generating. You will have to remove the end cover on the generator head to get access. Once again many pics are a big help for us to be able to assist you in figuring things out.
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  #38  
Old 08-07-2017, 06:30:03 PM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Will do Bigblockchev,

I will check things out if I get home before dark. to much work.

Thank you.
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Old 08-07-2017, 11:28:02 PM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Hi bigblockchev,
Ot is #35 tagged and it ohms to the best i can do it to abou3_17 ohms depending on the grip, now that is 1 wire without a mate on terminal block in contrl box, now i see another thinner wire coming into cntrl box from under it (assuming it looks to go into genhead? Ithink) and it goes from gen head to terminal blck and mates to wire that goes to starter solonoid oppsite side of b+ cable,? The other mistery wire coming from term blk ends with a eye crimp for a screw to attatch it. I thought before it had an end like oil pressure sensor but no it doesnt, see pic below in the morning when i get to work and down load pics. Frpm diagram it calls for it to go to fuel pump and then to relay emergency lop, and all i see is mechanical pumps???? Upload pics in the am
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  #40  
Old 08-08-2017, 12:12:15 AM
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Maybe the one wire with the eyelit on the end goes to the fuel pump shut-off solenoid?
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