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Onan 6.0 DJB-3CR C spec 1985 yr - Getting to run

DCWatmough

Registered
Hello Onan Masters! I am new to old Onans and this forum. I have learned a great deal after spending a couple hours reading previous posts about these wonderful, simple diesel generators. Thank you. This one can't have more than a couple hours of run time, just sat as residential backup. When I got it, I found the starter solonoid inoperative - took it apart, cleaned the contacts and had starter. Next was fuel system - drained & cleaned fuel filters, repaired pre-pump glass bowl leak [gskt] and used the manual primer to get fuel to the inj pump. Cranked it over and had fuel flow thru the return, figgured I'd fire it. Shot some PB Blaster into intake,cranked 'er, got her lubed up and then put the glow plugs to her. The old beast fired but didn't puff more than a couple strokes. Check for fuel delivery at the injectors,[remember my Dad doing that on his D4 Cat] and had none.Tried again with the PB but after keeping DJ running by direct injection down the intake, the head gskt blew. Found the govoner linkage seemingly frozen at the actuator shaft in the inj.pump.Tried freeing it but something was not right. I have no service manual for DJ and could'nt find an on-line one. So, I got my hands on a head gskt, replaced it, took the inj pump off and dove in. Took some time but after looking, poking,twisting & prodding I got the pump apart without mangling it. Cool & simple, found the plunger & fuel limiter [govener] stuck. Not much was corrosion, the working parts were fine so I cleaned & freed it all and reassembled DJ. I cranked it untill I had fuel to the injectors, primed it w/ some more PB and fired. A moment of rough running, cleared up and really ran well for a 3-5 min spell. Then she died.Fuel delivery ok @ injctors, so I took out the injectors - no spray. Shoulda' figguered that! [read a post that talks about a similiar situation] Now, I have disassembled the injector down to body and inner shield [a sleeve between the injectr & cooling body] and have determined that I have crud stuck in the inlet pressure side after the internal check ball and have reached a point where I can't figger out how to get the restof the injector apart. Anybody know how? Is it even possible? And, got suggestions on waking up the generator part.What can I service to help make sure that 3 times be a charm to success. Sorry for the long post, hopefully the details will help give the best direction to advise me. Thanks.
 

BTPost

Moderator
Staff member
Age
70
Last Subscription Date
12/29/2008
DCWatmough said:
Hello Onan Masters! Anybody know how? Is it even possible? And, got suggestions on waking up the generator part.What can I service to help make sure that 3 times be a charm to success. Sorry for the long post, hopefully the details will help give the best direction to advise me. Thanks.
First off, these injectors are very simple Bosch type injectors. Any good
Diesel Injector Rebuild Shop will have all the parts and the expertiese to
rebuild them. One of the things I always do, is completely flush the Fuel
System BEFORE I try Starting "A new to me engine". This eliminates any old crud from ending up fowling the Carbs or Injectors while I am trying to get things going. Second, I would drain and completely service the BaseOil/Oil Filter Lube System before trying to start the engine, paying specific attention
to any particals inside the oil filter when I cut it open, and inspecting the bottom of the bucket that the oil went into, for particles. What was the oil pressure, on the manual guage, while you were cranking the engine?

Bruce in alaska :D
 

Jim McIntyre

Subscriber
Last Subscription Date
07/10/2019
I'm sure you have lots of good experience starting Diesels using PB Blaster, but in my book, use of any fuel (ether, WD40, LPD86 or whatever) injected into the intake of an indirect injection engine is asking for trouble.

I know it's not related to your plugged injectors, but if the glow plugs are working, you won't need any priming.

If you're on a shoestring budget - keep at the injector disassembly yourself - you might get 'em fixed. Otherwise, now's a good time to stop in to a Diesel shop and get them rebuilt/tested.

Good luck, welcome to the board, and keep us posted on your progress.
 

dougfelsenthal

Registered
I have a similar problem. I have injectors out, new injectors to put in - but getting them removed from the 147-0133 heat shield seems to be a problem.

Looking for a technique - any comments welcomed.

Douglas
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
I put the injector assy in a vise upside down with heat shield on the top. I heat the aluminum heat shield with a propane torch. While heating I am gently prying up on the heat shield with a screwdriver. Take it easy and so far I have always been able to get them off without damage.
Your heating aluminum don’t get it too hot and melt it.
David
 
Last edited:

dougfelsenthal

Registered
David,
Thanks for the return message. Maybe you would have some thoughts on my situation.

This is an Onan DJB - 130hours - old of course. I serviced about two years ago. It's run maybe 5 hours since then. It has been doing great until I wanted to sell my house and it became very hard to start. It seems to me, it was just running on one cylinder. It sputters and fires but not in a consistent manner. Puffs of white smoke bounds out once in a while.

Cleaned fuel bowl - it fills well.

I checked the glow plugs, made sure hot and electrical going to them was good.
Checked air heater in intake - looking good there also.

Next I selected a cylinder, this case left when looking at panel. It seemed to be somewhat dry on the outside, unlike the one on the right.
Pulled the injector, way easier than I thought. I appeared to me, the bore was a medium dark gery, but certainly dryer than I would expect. I am now socking the injector to clean off tip.

One question, this was not bolted down to more than 20ft-lbs. Do you know the appropriate amount. It was less tight than I would have expected.

Fuel seemed to be in both input lines

Can you think of anything else I should be checking or doing. If I can't determine if the left injector is going, I'm going to try and get a new one. Once I'm sure the left is up to snuff, if it still needs help I'll pull the right. Mechanically, I can't see anything wrong or hear anything either. It's been a good runner, then all of a sudden not so good.

I'm going to be overthere later, if you think some pics would help, I'll send them along. Let me know.


Thanks in Advance,


Douglas
 

nothingbutdarts

Sponsor
Last Subscription Date
08/15/2019
You could try swapping injectors from one cylinder to the other, than start it & feel the exhaust manifold to see if they both appear to be the same temperature, if one is much colder than the other than swap the injectors back & see if the cold cylinder follows the injector swap or not.
Have you given the engine a chance to actually warm up with a load on it? Sometimes just putting a good load on a diesel set will let them clean up and run much better.
 

dougfelsenthal

Registered
Let me first thank those that have gotten back to me. Still having trouble.

I went over with my cleaned up injector to see if I could get something going. Nothing was happening.

Appears I have no output from the injection pump. Just a dab - can you believe this thing was running just a couple weeks ago.

Checked the low pressure fuel and after the filters. Sediment bowl is full. All seemed good to that point.

I disconnected the injector pump lines - turned transfer switch to manual and put it on start. Nothing comes out of either line. Strange right - you would expect something.

Is there any special way of checking the pump for output? I am assuming that by just turning the engine over that I should see some output. Right?

Am I missing something that is shutting off the fuel and giving me a false experience? I expecting that the crank will turn the pump over, but is there some sort of shut off value that I have hold open?

Any ideas are greatly appreciated.


Thanks in Advance,


Douglas
 

zuhnc

Subscriber
Last Subscription Date
12/08/2019
Make sure that the fuel shut-off solenoid is operating properly, and the governor spring is holding the fuel rack/arm on the injection pump wide open, with the unit not running, but cranking. Make sure that said rack pivots freely. zuhnc
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
Douglas do you have the service manual for this DJB? If you don’t just ask and someone here can tell you which manual you need and where to download it. It will give you Almost everything you need to test and repair. You need to post your model and serial number as it will be needed for the proper manual. It will help you with repairs and better describe exactly what is going on. We all will continue to help until you are up and running.

David
 

dougfelsenthal

Registered
Thank you VelocityDave,

I do have an operations and parts manual. But this does not have any real service articles. So if someone has something that would help me trouble shoot the injection pump and service things it would be great.

It's a DJB-3CR-IS spec S
DJB-21
S/N 469828

I still have the orignal build sheet on this.

It looks just great and has been running well till just recently. That is if you consider 5 hours a year great! i'm sure if I get fuel into it - it will go.

Thanks for all your help out there.


Douglas
 

VelocityDave

Subscriber
Last Subscription Date
06/23/2019
Douglas if this is a older magnaciter generator and it is running slower than 1800 rpm it will burn up the voltage regulator section of the generator. If it has a YD generator end you are ok. 60 hz = 1800 rpm.
A magnaciter must NOT be ran slow or the magic smoke will be let out.

David
 

BigBlockChev

Subscriber
Last Subscription Date
07/06/2019
One weird little item is the T on top of the injection pump it has a spring loaded relief valve in it which maintains a positive back pressure in the injection pump body to make sure that fuel actually gets to the pump piston instead of bypassing back to the return line. I have seen these cause problems at times. They LOOK exactly like a regular fuel T. Cheers Dan
 

dougfelsenthal

Registered
Thank you gentlemen, this is real helpful. I'm going over tomorrow and poke around. Some reading here will get me primed. I'm going to check all the fuel priming articles first. Since it has operated satisfactorially in the recent past, I'm hoping it can be something simple.

Thanks again for all of your information so far.


Douglas
 

dougfelsenthal

Registered
I can't thank everyone enough for the help - that is quite a list of manuals.

I'm leaning towards some priming issues at the moment. If anyone has any hacks etc for priming and checking the results let me know. I'm thinking about changing out the fuel filters just as good measure - they aren't that old though. My priming lever acts a little old, but if I empty the fuel bowl it fills back up again. I'm going to measure low side fuel pressure today - It flows well, but not sure what the pressure is.

Question: Has anyone bypassed the mechanical fuel pump and put in an electric one. My gas onans all use electric ones. I would be easier than trying swap out the mechanical one for a test.

I've got a set of injectors at the ready, but can't verify that is the problem since there is not enough fuel getting up that far.

Question: If I have to, does anyone know of someone who can rebuild the injection pump? The installer, Flaherty Equipment has since gone out of business. I could go directly to Cummins, but haven't had kind luck with them in the past.

I just can't believe that the injector pump would go from working to nothing all at once. I'm sort of leaning if the throttle value or something is not quite right. Since I get nothing - it's like it's not opening either externally or internally.

Thanks again in Advance of all the kind help and guidance.


Douglas
 
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