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DJB fuel transfer pump rebuild?


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  #1  
Old 04-07-2008, 12:07:45 AM
jas67 jas67 is offline
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Unhappy DJB fuel transfer pump rebuild?

Is it possible to rebuild the transfer fuel pump on a DJB?

I worked on getting my newly-acquired 6.0-DBJ-3C started today. It now has fresh oil, new filters, and a battery. It cranks, and the manifold heater works.

This thing is a (!@#$%^&@# to prime. I really have to pump fast to get it to prime. I finally ended up removing the fuel line that goes between the pump and the filters, and putting my fuel source higher than the pump to get it to prime. Once primed, the problem became evident. I have a leak. It is seeping all around the edge of the pump (where the two halves meet).

I can fix this, or do I need a new pump?
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  #2  
Old 04-07-2008, 05:55:20 AM
Gunny Gunny is offline
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Default Re: DJB fuel transfer pump rebuild?

Many years ago, you could purchase a rebuild kit from Onan. Not sure if still in the system.

You could abandon that lift pump and install and electric.
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  #3  
Old 04-07-2008, 07:30:42 AM
Patrick Patrick is offline
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Default Re: DJB fuel transfer pump rebuild?

Not familiar with the model at all, but can you split the pump where it is leaking, and cut yourself a new gasket from a sheet of gasket material?
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Old 04-07-2008, 08:26:02 AM
jas67 jas67 is offline
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Lightbulb Re: DJB fuel transfer pump rebuild?

This though crossed my mind after I posted. That would certainly make priming a lot easier too. I assume that an automotive low-pressure electric fuel pump like you'd retrofit to a carbureted car would work?

Should I just remove the mechanical pump and fabricator a cover to put in its place, or just leave the pump there?

Quote:
Originally Posted by Gunny View Post
Many years ago, you could purchase a rebuild kit from Onan. Not sure if still in the system.

You could abandon that lift pump and install and electric.
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  #5  
Old 04-07-2008, 09:06:57 AM
jas67 jas67 is offline
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Thumbs down Re: DJB fuel transfer pump rebuild?

Gunny,

If I do remove the mechanical pump and replace it with an electric one, do I need to add something to replace the sediment bowl that is on the mechanical pump?

Can you recommend an electric pump? Would an automotive one designed for gasoline be suitable for diesel fuel?

Thanks again,
Jay
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  #6  
Old 04-07-2008, 09:07:01 AM
Jim Rankin Jim Rankin is offline
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Default Re: DJB fuel transfer pump rebuild?

First thing to try is simply tightening the fastners that hold the two halves of the pump together. Or you could disassemble it and use some brush on gasket sealer/maker just on the flanges of the pump to keep it from getting all over the diaphragm.

When the diaphragm is gone, it should leak fuel out a weep hole in the pump body (or fill the oil pan with fuel) so pay attention to the condition of the oil. Your oil level may rise as you run it.
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Old 04-07-2008, 07:31:35 PM
Gunny Gunny is offline
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Default Re: DJB fuel transfer pump rebuild?

Having tinkered with those things a lot through the years...........

Some of the later ones were riveted together, if held together with screws, tightening them might get the leak to stop, for a while.

If held together with screws, you might be able to take it apart and cut a new gasket, if you can find suitable material as the gasket is also the diaphram. If you do go this way, there are 2 check valves in there and one of them is probably the reason it isn't moving fuel like you'd like for it to. If the diaphram is deteriorated and coming apart, a real good chance that a piece of it is lodged in one of the check valves.

If it were mine, I'd make a cover plate to cover the hole in the block, remove the pump and go with an electric one. A low pressure automotive will work fine. I've done a number of them as Onan is extremely proud of a new one, an electric can be had for about $30.00. A benefit of an electric, makes it real easy to prime the fuel system after a filter change, just power up the pump off of the battery with the bleed port open.
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Old 04-07-2008, 07:44:55 PM
jas67 jas67 is offline
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Default Re: DJB fuel transfer pump rebuild?

My pump is screwed together, but I think I'll go with an electric one as you suggested. The DJx service manual specifies 14 PSI in the transfer pump test. Most low pressure automotive pumps seem to be around 4 PSI. Will one of these work (I would assume not)?

Thanks again,

Jay
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Old 04-08-2008, 07:24:19 PM
Dslsmoke Dslsmoke is offline
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Default Re: DJB fuel transfer pump rebuild?

Quote:
Originally Posted by Gunny View Post

If it were mine, I'd....go with an electric one. A low pressure automotive will work fine. I've done a number of them as Onan is extremely proud of a new one, an electric can be had for about $30.00. A benefit of an electric, makes it real easy to prime the fuel system after a filter change, just power up the pump off of the battery with the bleed port open.

Makes good sense to me, Is this one up to par? http://www.autozone.com/R,NONAPP3338...ductDetail.htm

If so, Do you just hookup a separate (fused) line from the batt. with a toggle switch to the pump, or would you suggest a more automated way?

I just picked up ( 2 ) 65 gal. aluminum saddle tanks from a big rig and will be doing the hook up soon.


Thanks:
Dslsmoke
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  #10  
Old 04-08-2008, 08:25:19 PM
Gunny Gunny is offline
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Default Re: DJB fuel transfer pump rebuild?

That pump should work just fine.

You want to land the positive side of that pump to a terminal on the fuel shut off solenoid that picks up 12VDC when the engine runs. That way if it shuts down for whatever reason, fuel pump shuts off automatically.

(2) 65 gallon tanks? 1 would run it for a real long time. I'd consider using only 1 so the fuel doesn't absorb water and go bad on you before you get a chance use it up.
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Old 04-09-2008, 05:44:31 PM
JCarroll JCarroll is offline
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Default Re: DJB fuel transfer pump rebuild?

Gunny, correct me if I am wrong - a DJB uses .66 gallons / hour, so 65 gallons would run it for 98.48 hours or 4.1 days.
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  #12  
Old 04-09-2008, 07:48:20 PM
Gunny Gunny is offline
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Default Re: DJB fuel transfer pump rebuild?

That is correct. At full load, if lightly loaded, it will use even less, run longer.

I have a 100 gallon tank for my 12.5 DJC, its full now and expect it would run about 4 days if run continuously. If we do have an extended outage and if the weather is fair, don't need AC or heat, figure I could make it last a week or more, then start getting some fuel out of the drums stored in the shed. I stocked up on fuel for Y2K at $1.25 a gallon and hate to start using it cause it would cost 3 times what I paid for it to replace it.
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Old 04-09-2008, 09:45:29 PM
Dslsmoke Dslsmoke is offline
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Default Re: DJB fuel transfer pump rebuild?

Quote:
Originally Posted by Gunny View Post
That pump should work just fine.

You want to land the positive side of that pump to a terminal on the fuel shut off solenoid that picks up 12VDC when the engine runs. That way if it shuts down for whatever reason, fuel pump shuts off automatically.
Will that also hold true for the DJC? That's what I have just like you, 12.5 DJC.

Do you suggest getting power from the solenoid it self, or from the control board?

If from the board, where exactly?

Quote:
I have a 100 gallon tank for my 12.5 DJC, its full now and expect it would run about 4 days if run continuously.
When Wilma hit Miami a couple years back, we lost power for 14 days, good thing I had my 4.5KW Yanmar Diesel.
I was running it at ½ to ¾ load and getting 9½ to 10 hours from each 5 gal tank.

Quote:
(2) 65 gallon tanks? 1 would run it for a real long time. I'd consider using only 1 so the fuel doesn't absorb water and go bad on you before you get a chance use it up.
Well, they were free, I just couldn't pass up that deal, I also have a 55gal. plastic drum that I keep in the shed (empty at this time) just as a back up.
But like you said, Diesel here is going for $4.09/gal. and if I fill up completely, that's 185 gallons of fuel for a total of nearly $760 plus fuel additives and stuff, now your talking big $$$$


Quote:
That is correct. At full load, if lightly loaded, it will use even less, run longer.

I have a 100 gallon tank for my 12.5 DJC, its full now and expect it would run about 4 days if run continuously. If we do have an extended outage and if the weather is fair, don't need AC or heat, figure I could make it last a week or more, then start getting some fuel out of the drums stored in the shed. I stocked up on fuel for Y2K at $1.25 a gallon and hate to start using it cause it would cost 3 times what I paid for it to replace it.
That leads me to the next Question,
How long can you store Diesel without it going bad on you?


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Dslsmoke
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  #14  
Old 04-09-2008, 10:04:21 PM
VaughnSimon VaughnSimon is offline
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Default Re: DJB fuel transfer pump rebuild?

Quote:
Diesel here is going for $4.09/gal. and if I fill up completely, that's 185 gallons of fuel for a total of nearly $760 plus fuel additives and stuff, now your talking big $$$$
That is one of the really nice things about natural gas. It connects you straight to the main supply and you don't have to buy a drop until the moment you need it. (Yes, I know, the NG system can go out, but in the last three hurricanes it hasn't. I keep a couple 100# LP tanks full just in case)

Vaughn
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Old 04-09-2008, 10:15:33 PM
Dslsmoke Dslsmoke is offline
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Default Re: DJB fuel transfer pump rebuild?

I can, and have purchased Off road Diesel, there is a small saving in taxes, about 25 to 35 cents per gallon, but have to travel a distance, or have it delivered "there goes the savings"

How long were you with out power during Wilma?


Dslsmoke.
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Old 04-10-2008, 05:47:18 AM
Patrick Patrick is offline
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Default Re: DJB fuel transfer pump rebuild?

I've used diesel I found in a sealed tin (from back in the days when you could just go and buy a gallon can of diesel!), it was 25 years old according to the design on the can. Worked just fine, just the same as any other diesel. I used it up, then sold the empty can on Ebay for three times the price of a gallon of diesel these days! (about $10 a gallon where I live)
Also did the same with a 15-year old can which had been opened, it too worked fine.

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Old 04-16-2008, 07:45:45 PM
jas67 jas67 is offline
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Unhappy Re: DJB fuel transfer pump rebuild? (update)

I have the electric pump connected in place of the mechanical lift pump. I turned it on, and let it run for about 10 minutes, but still nothing comes out the return line from the injection pump

The DJx service manual states that all that is need to bleed the full system is to actuate the level (on the mechanical pump) until fuel comes out the return.

Am I missing something?

I loosened then connection at the input to the fuel filters, and got fuel seepage, so I know the new pump is pumping.

This pump is spec'd for 4-7 PSI. The service manual specifies 14 PSI for the mechanical pump, but Gunny said in another post that a 3 PSI pump should do the job.

HELP

Thanks,
Jay
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Old 04-16-2008, 09:02:40 PM
Gunny Gunny is offline
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Default Re: DJB fuel transfer pump rebuild?

That pump should work just fine.

I've used 3 psi pumps with no problem.

Are you getting seepage or good fuel flow from the secondary filter? Is it foamed up? If so, you have an air leak in your suction side, somewhere. Possible clogged filter? Suction line collapsing?
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Old 04-16-2008, 10:55:55 PM
jas67 jas67 is offline
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Thumbs up Re: DJB fuel transfer pump rebuild?

I don't know if it has good fuel flow or not. I just cracked a line loose to see if anything was there. The fuel line fittings from the filter to the injection pump are pretty rusty, I'm half afraid to crack one of those open, for fear of breaking something.

I don't think that the suction line is collapsing. It isn't anywhere that I can see it (right now, there is just about 14" if it directly down into a 5 gal plastic jerry-can). I'm using automotive fuel hose, and have it inside a piece 3/4" down into the fuel can to keep it strait, and the end in fuel. The filters are all new. I'll double-check my threaded fittings on the pump to make sure I have no air-leaks there.

Thanks,
Jay
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  #20  
Old 04-17-2008, 02:27:49 AM
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Talking Re: DJB fuel transfer pump rebuild?

Jay, all that should be needed is to make sure that you have good fuel flow to the Input
at the Injection Pump. Once you are sure you have that, then it is time to crank over
the engine with the Injector Lines cracked at the Top of the Injectors. Crank the engine
the engine untill you have fuel dribbling from each Injector Line. Then retighten the
Injector Lines and your ready to go for a Hot Start. Make sure you have a Good stiff
battery, and heat the glowplugs and Manifold Heater for 60 - 90 Seconds, then give
it a spin. You should get some white smoke after about 10 seconds, and at least a
good Pop, or Two, after 30 seconds of cranking. Onans DJ's are a bit Cranky when
you are first trying to start them, but once you get them to run, and get them warmed
up they restart, easily.
__________________
Bruce in alaska
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