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Onan 12.0DJC Manuals and Info for newbie!


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  #1  
Old 09-09-2017, 09:23:14 PM
Blasko Blasko is offline
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Default Onan 12.0DJC Manuals and Info for newbie!

Hello all! I'd like to say that from what I've seen so far this is a very well organized forum!

I apologize if this is a long post. I'm in West Palm Beach and this silly hurricane was making me wonder if i could get this thing working for me.

(Disclaimer i have a few Honda gas generators on standby that work fine. The Onan is NOT my only backup)

I'll just start from the beginning!

A friend of mine used to keep it at his camp in the woods in northern Florida
The only knowledge i have on it is that it ran and shut off when it got hot. No more info than that really. I brought it home and it sat for around 6 months until The other day. It wouldn't turn over. I made a plate and bolted it to the fan. With leverage it easily broke free. It ill turn over for me now. I got it to fire one stroke only.I have done a bit of cranking on it but I do not want to burn up the starter. The starter could use replacement, but for now it seems to work when it wants to. For now I just would like to find the manuals and do some learning/ research before I ask for your time online.

I've seen the chart. According to what info I've found, The operators manual I'm looking for would be 967-0122. I have seen links to this "twinslan.net" and their website will not work for me. If someone could direct me to another source that would be incredible. Email would work too! (furnish@me.com)

I've attached a photo of my serial just in case I've found wrong information!!

Thank you ahead of time for your help!
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Old 09-09-2017, 09:29:41 PM
KPack KPack is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

That site is down right now.
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Old 09-09-2017, 10:07:37 PM
MBB MBB is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Sending Manual.

You will get almost full Amps from unit.

Last edited by MBB; 09-09-2017 at 09:46:37 PM.
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Old 09-09-2017, 10:15:33 PM
len k len k is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Check for mouse nest in control box, they like to pee on everything inside and ammonia corrodes all the contacts and connections. Not bad idea to check for mice nest in genhead and 120/240 reconnection box that's ~ below control box. Mice nest 2/3 filled my reconnection box and peed over all the wire nuts, corroded everything. I had to cut off the nuts clean and reconnect.

The 2 inch tall penthouse above control box contains the electronic AC voltage reg. So your gen should have a YD type genhead. ( not a magnaciter)
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Old 09-09-2017, 10:27:48 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Are the glow plugs and intake heater working? They draw quite a few amps all by themselves!
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Old 09-09-2017, 10:44:37 PM
len k len k is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

DJB takes ~ 48 amps total for 2 glow plugs and carb heater, so would expect DJC to draw ~ 100.
2 VS 4 cylinder.
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Old 09-10-2017, 12:16:50 PM
Blasko Blasko is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Quote:
Originally Posted by KPack View Post
That site is down right now.
I just hope it comes back online in the future for future references!

Quote:
Originally Posted by MBB View Post
Sending Manual.

You will get almost full Amps from unit.
Thank you very much I appreciate it wholeheartedly

Quote:
Originally Posted by len k View Post
Check for mouse nest in control box, they like to pee on everything inside and ammonia corrodes all the contacts and connections. Not bad idea to check for mice nest in genhead and 120/240 reconnection box that's ~ below control box. Mice nest 2/3 filled my reconnection box and peed over all the wire nuts, corroded everything. I had to cut off the nuts clean and reconnect.

The 2 inch tall penthouse above control box contains the electronic AC voltage reg. So your gen should have a YD type genhead. ( not a magnaciter)

haha penthouse! I have not taken the control box cover off yet. I will after this hurricane to further inspect. Thank you for your information!


Quote:
Originally Posted by nothingbutdarts View Post
Are the glow plugs and intake heater working? They draw quite a few amps all by themselves!
After holding the heat switch, yes I can feel the heat on the outside of the air box just outside of the glowplugs

Quote:
Originally Posted by len k View Post
DJB takes ~ 48 amps total for 2 glow plugs and carb heater, so would expect DJC to draw ~ 100.
2 VS 4 cylinder.
Thank you for this information.







Last Time I cranked it i did see smoke which leads me to believe it is getting fuel. I just would like to check that its getting g the RPM it needs during cranking. I'm going to research the mechanics of the decompression valve/solenoid and Maybe look into a replacement starter. This one does turn it over fast enough for me to think it would start, but gets hot pretty quickly and sometimes has a hard time as if its in a bind every other few start attempts

Thank You
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Old 09-10-2017, 12:52:19 PM
len k len k is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

100 amp preheat is a lot of amps for a car bat, so maybe add FAT copper jumpers and a running car to supply the extra energy.

I'm not into diesel much, but remember others here saying sometimes have to bleed air out of lines to the injectors. Crack loosen the line at injectors and crank till bubbles stop I think. Also there is some prime lever on fuel pump that feeds injector pump. Others here know diesel better.

Be careful injector lines run over 1000 psi, maybe 1700. and leaks can act like a pressure washer. Diesel can be injected under your skin, I hear solution in usually amputation. Be careful of those high pressure lines.

Last edited by len k; 09-10-2017 at 09:28:54 PM. Reason: typo
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Old 09-10-2017, 09:24:19 PM
Blasko Blasko is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Quote:
Originally Posted by len k View Post
100 amp preheat is a lot of amps for a car bat, so maybe add FAT copper jumpers and a running car to supply the extra energy.

I'm not into diesel much, but remember others here saying sometimes have to bleed air out of lines to the injectors. Crack loosen the line at injectors and crank till bubbles stop I think. Also there is some prime level on fuel pump that feeds injector pump. Others here know diesel better.

Be careful injector lines run over 1000 psi, maybe 1700. and leaks can act like a pressure washer. Diesel can be injected under your skin, I hear solution in usually amputation. Be careful of those high pressure lines.

I learned about diesel only from buying a non running power stroke and making it run. although my t ruck is HUEI, I do understand that this generator makes high fuel pressure. Also this generator has an electric fuel pump and the mechanical one is bypassed. I'm not sure if I said that yet.

Thank you for your reply. I appreciate your time and energy to reply to me.

I haven't bled it yet, But i will give it a try!
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Old 09-10-2017, 09:28:46 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

I do not believe a DJC has a decompression solenoid. it does however have a shut-off solenoid which when it has no power applied it pushes the the arm to no fuel position on the fuel pump, when power is applied it pulls all the way up off the arm.
Also it has 4 glow pulgs, one in each cylinder, you might want to ohms check each glow plug individually as in the power wire disconnected from the glow plug. It shgould have very low resistance, maybe somewhere around 10 ohms I believe.
Once you verify that the plugs are good than check voltage while heating the syst.

They are a bit hard starting especially if the heater syst. is not fully working.

Last edited by nothingbutdarts; 09-10-2017 at 09:31:37 PM. Reason: addded info.
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Old 09-10-2017, 09:31:04 PM
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BigBlockChev BigBlockChev is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Bleed it at the injectors, preheat for 1 minute, and make sure you have a good battery , thick battery cables and good connections and it will start. With an electric fuel pump it is easier to see fuel coming from the return line if y ou run the pump for a couple minutes before starting cranking. Post your results and we will see if we can get you going. Cheers Dan
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Old 09-10-2017, 09:57:28 PM
len k len k is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

A 6DJB draws 50 amps for preheat, 2 cylinder engine. Think I remember ~ 1/2 that is for intake heater. So each glow plug might draw ~12 amps, so I'm thinking each glow plug is ~ 1 or 0.9 ohm

DC clamp on ampmeter would tell if each glow plug were working. Lacking that, crude but a compass near the power wire to each one, see if and how much compass moves.
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Old 09-12-2017, 10:44:20 PM
Blasko Blasko is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

Quote:
Originally Posted by nothingbutdarts View Post
I do not believe a DJC has a decompression solenoid. it does however have a shut-off solenoid which when it has no power applied it pushes the the arm to no fuel position on the fuel pump, when power is applied it pulls all the way up off the arm.
Also it has 4 glow pulgs, one in each cylinder, you might want to ohms check each glow plug individually as in the power wire disconnected from the glow plug. It shgould have very low resistance, maybe somewhere around 10 ohms I believe.
Once you verify that the plugs are good than check voltage while heating the syst.

They are a bit hard starting especially if the heater syst. is not fully working.
Okay thank you for your information! I grabbed my temp gun and all 6 Glow plugs get hot. The 4 smaller one get hot evenly as intended. Awesome!

Quote:
Originally Posted by BigBlockChev View Post
Bleed it at the injectors, preheat for 1 minute, and make sure you have a good battery , thick battery cables and good connections and it will start. With an electric fuel pump it is easier to see fuel coming from the return line if y ou run the pump for a couple minutes before starting cranking. Post your results and we will see if we can get you going. Cheers Dan
By bleed at the injector I can only assume i have to bleed while cranking or else their won't be fuel flow due to the timing of the pump?

Also my return line 'T's back into the supply just before the pump so If there is air it won't make it out, I'll change that next.


Quote:
Originally Posted by len k View Post
A 6DJB draws 50 amps for preheat, 2 cylinder engine. Think I remember ~ 1/2 that is for intake heater. So each glow plug might draw ~12 amps, so I'm thinking each glow plug is ~ 1 or 0.9 ohm

DC clamp on ampmeter would tell if each glow plug were working. Lacking that, crude but a compass near the power wire to each one, see if and how much compass moves.
I somehow could not find my clamp meter, But as i mentioned in a quote above, With my temperature gun I was able to verify the 6 glow plugs work and get hot. The intake air heaters got the intake to almost 300℉ fairly quickly!










I'm going to post a few photos with quick questions I have as newbie. I first wanted to say that i really appreciate your time in helping me with my issues and questions. I still have no power other than my gas generator in FL as of now, so once I can get some batteries charged up full I'm going to try to fire the 'ole girl up again. Until then I'm going to work on the wiring cleaning her up and such.

QUESTION 1 is this first photo. I'm ASSUMING There is supposed to be a duct from the geneset the vents on the case so that if the doors are on it gets fresh air. I can't see how else it would be. Just making sure.





My second Question involves these next 3 photos. On the door with all my gauges I found this 2 position switch. Now in the last photo you see broken wire where all the switches are disconnected form the gauge box, but the ones on the gun set themselves are still fine. What would that switch have done?





]
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Old 09-12-2017, 10:50:43 PM
Blasko Blasko is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

I could only do 4 photos a a time so here are the lats 4
What would this connection on the exit side of the air cooling near the heads be for? and why is it placed there?









Here is how my outlets are set. Was just curious what the typical installation would be because I assume this is nothing like factory.






Lastly is that are these for? I understand that the second one is a centrifugal switch, But what does it control?


THANK YOU FOR YOUR TIME

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Old 09-12-2017, 11:05:26 PM
yellowlister yellowlister is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

the 2 switches under the gauges are your breakers that trip when to many amps are drawn.. wires look like they go to the gauges but not sure

The centrifugal switch disconnects the starter when it gets to a certain rpm
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Old 09-12-2017, 11:44:30 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

In your post # 14 asking about the wires on the air outlet, the set had a High Air temp. shut off switch that has now been bypassed.
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Old 09-13-2017, 12:00:02 AM
Steve Dawkins Steve Dawkins is offline
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

To answer some of your questions:

1. From the factory, there was a piece of flexible duct to bring cooling air from outside the enclosure into the generator end to cool the windings.

2. The toggle switch above the meters may be for panel lights. Are there any 12 volt lights located above the control panel?

3. The wires in the engine hot air discharge are probably for a high temperature shutdown switch.

4. The round thing in the rectangular opening is the battery charge resistor. It gets hot, and is placed in the air discharge of the generator cooling fan.

In your photo of the centrifugal start disconnect switch, there is a spring on a shaft behind the centrifugal switch. They connect to the stop solenoid, which pushes the throttle arm to stop the engine. That spring and shaft should retract while the engines starts and runs. Make sure they move freely.

Last edited by Steve Dawkins; 09-13-2017 at 10:51:48 AM.
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Old 09-13-2017, 12:08:52 AM
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Default Re: Onan 12.0DJC Manuals and Info for newbie!

"T" ing into the supply line for fuel return is a good way to waste a lot of time trying to purge the air out of the fuel line. The return should go all the way back to the fuel tank to avoid just recirculating the air bubbles into the supply line. Yes bleeding while cranking is necessary to get the air out of the lines. If you can loosen the big fuel line nuts at the injector that will prove fuel all the way to the injector, once you see fuel squirt out between the nut and line you can re tighten the nut. Can you verify that the fuel solenoid is retracting while 'the gen is cranking , the plunger is just behind the centrifugal switch. Usually it makes a bit of a clunk when activated but if you can see it so much the better. The centrifugal switch takes over supplying 12V to the solenoid once the speed gets up to 900 rpm. You can test the set by pushing the plunger up with a screwdriver while cranking, that will allow the lever on the IP to be pulled up by the governor linkage and fuel can then flow. Cheers Dan
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