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Diesel Injector Service--Remove/Replace and Bleeding

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I couldn't find a thread on what is a recommended service: cleaning and maybe rebuilding fuel injectors on Universal diesels.

Any known pitfalls?

The books say clean the block carefully so junk doesn't fall into the cylinders. Remove the steel fuel tubes without bending them much, and probably as a unit. Remove the blow-by lines connecting the injectors one to another.

I concluded (by reading) that testing and hand-cleaning are probably not sufficient, and that the simple solution is to take the injectors to a diesel shop for a professional assessment, testing and cleaning. They're simple in theory but the tolerances and spray pattern are crucial.

At the moment I have the fuel feed lines off, which was easy enough although required one new (short) 11/16th/17 mm spanner since E38 access is not great. Yesterday I squirted some PB Blaster on the injector threads to prepare for today's attempt at removal. wrenches.

I ought to have done this before the long cruise. When I asked Martin Ball, who did my initial engine survey, what maintenance the M40 needed beyond the usual, he said "Well, you could have the injectors checked out."

I doubt most of our engines have had it done, even after 30 years.
 
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Joliba

1988 E38-200 Contributing Member
injectors

I did this on our Universal 5432 a few years ago. I needed to fashion a long socket by cutting away part of one I bought at Harbor Freight with with a grinding wheel because there was not sufficient clearance to fully insert the standard socket. I bought new rubber fuel lines and clips from Kubota. I had the injectors tested and serviced at a reputable diesel injector shop. Don't forget to use new little brass washers that the injector shop will give you for re-seating the serviced injectors. (And don't forget to remove the old washers.) Also, make note from which cylinder each injector is removed and label it. (I can't remember why that was important, though.)
The engine ran much better after this, but we did some other things st the same time. So, I'm not certain if the cleaned and repaired injectors were responsible.
Not a bad thing to do for an old engine.
Mike Jacker
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Thanks, Mike. I just returned from the boat , where I found that the 1 1/16th socket won't fit--not quite enough side clearance. And a big spanner can't quite get a grip given the limited space.

I'll try modifying a socket, as you did. It will have to be a long socket, the standard one I bought was't deep enough.

I've been soaking the injector threads in PB Blaster. I see no corrosion, but looks like they'll need a solid wrench fit and some persuasion to release. Maybe an impact hammer.

I have removed the fuel lines, flow rings and connecting hoses, but there's yet another ring remaining (lower of the so-called 'double nipple'.) Do you recall if you removed both rings before extracting the injector?

injector photo.JPG
 
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Brad Johnson

Member III
I couldn't find a thread on what is a recommended service: cleaning and maybe rebuilding fuel injectors on Universal diesels.

Any known pitfalls?

The books say clean the block carefully so junk doesn't fall into the cylinders. Remove the steel fuel tubes without bending them much, and probably as a unit. Remove the blow-by lines connecting the injectors one to another.

I concluded (by reading) that testing and hand-cleaning are probably not sufficient, and that the simple solution is to take the injectors to a diesel shop for a professional assessment, testing and cleaning. They're simple in theory but the tolerances and spray pattern are crucial.

At the moment I have the fuel feed lines off, which was easy enough although required one new (short) 11/16th/17 mm spanner since E38 access is not great. Yesterday I squirted some PB Blaster on the injector threads to prepare for today's attempt at removal. wrenches.

I ought to have done this before the long cruise. When I asked Martin Ball, who did my initial engine survey, what maintenance the M40 needed beyond the usual, he said "Well, you could have the injectors checked out."

I doubt most of our engines have had it done, even after 30 years.

I had mine rebuilt on my M12 about 15 years ago with about 1000 hours on the engine, I did it because it started to smoke at the high end of cruising RPMs , I have maybe 1500 on her now and it is still running like new , I do not remember any real problems doing the removal or instillation, but I do remember that the price was $100 each for the rebuild.
 

Joliba

1988 E38-200 Contributing Member
injectors new return lines.jpg
Christian,
I removed everything up to that last nut. I believe that is where you are. The last thing I removed was the ring with the horns (arrow in photo). The rest came out with the injector. (Whatever fits in the socket can be removed later.) I put the parts for each one in a separate labeled ziplock bag for later reassembly. The injector shop should be able to make them work like new...much cheaper than new ones. They should also be able to give you a printout of the quantitative results of the testing and the interpretation by injector #. (Its a learning experience.) As I recall from this forum, people paid $50-80 per injector. That was a few years ago. If you do buy it new, get it from Kubota, not Westerbeke (Universal)... Identical part.
Yes, it was a long socket that I modified. I did not need PB Blaster. One tap on a long socket handle and the rest was easy. Reinstalling, I used a torque wrench to specifications. However, as I recall this did not seem tight enough, so I made it a bit tighter. You only get one chance to tighten them because the brass (copper?) washer that they will provide deforms with the tightening and is part of the seal of the injector in its seat. I bought all the new fuel return hoses from Kubota.
Mike
 

Joliba

1988 E38-200 Contributing Member
One more thing

In addition to the copper washers, a mechanic gave me a tube of anti-seize to put on the injector threads when reinstalling them. At times, we all grumble about the PO. I guess this is to be kind to the NO of our boats.
Mike
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
In my case a Husky 1 1/16" deep socket fit pretty well over the injector body. The injector doesn't seem to be torqued very hard, and the breaker bar I used was probably not necessary.

However, the fuel blow-by ring has to come off first, and that was the bear.

It is necessary to get a grip on the center of the injector with a separate wrench--a 15/16th spanner works. Then break free the top nut with a standard socket wrench and some encouraging words.

Anyhow, the injectors are out in one piece. Monday off to a diesel shop to see about rebuild and testing.

FI breaker bar.jpg

1-FI big spanner.JPG1-FI injectors & all.JPG
 
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Anybody know how the injector bleed valve on the 5432 is supposed to work?

In bleeding air, I get fuel spurt from engine fuel filter, but when opening the knurled knob to continue the air bleed at the injectors, nothing happens (even while the engine is running).

This "nothing happens" was reported by several other 5432 owners. But I think my valve is broken--the knurled ring screws right off, leaving behind its axis. Isn't the whole unit supposed to turn out so fuel can spurt?

The injectors are installed and the engine starts instantly, but there's a god-awful knocking sound like we threw a rod. Mechanic friend says it's air still in system.

This photo of the valve in question is from another boat.

fuel_pump_and_bleed_valve_marked.jpg
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
on our M25XP (1988), turning that valve lets new fuel thru it and then into the return line back to the tank. When we power the electric lift pump, it clicks noisily, at a higher noise rate when the valve is open, and slows down when I turn the valve closed. This "bleeds" the air out of the system up to that point, which is adjacent to the high-pressure pump.
I have also opened (and bled out) air up to the bleed plug on the filter housing on the side of the engine.

I wonder if your engine has a valve where the little wheel is no longer connected to the shaft? (Caution: I actually have no idea exactly what I am talking about...)
:rolleyes:

Loren
 

Joliba

1988 E38-200 Contributing Member
But I think my valve is broken--the knurled ring screws right off, leaving behind its axis. Isn't the whole unit supposed to turn out so fuel can spurt

Christian,
Yes, from your description, your valve sounds inoperative. Replacements can be obtained from Kubota. Mine used to bleed air and then drip fuel when bleeding. Though I think the last time I tried it I saw no fuel. Maybe mine is broken, too? Nonetheless, conventional bleeding by loosening then tightening the pipes on the injectors should bleed it.
Did the "knocking" stop in short order? It seems to me that once the engine is running on all cylinders any remaining air would bleed itself.
Mike
 

footrope

Contributing Partner
Blogs Author
on our M25XP (1988), turning that valve lets new fuel thru it and then into the return line back to the tank. When we power the electric lift pump, it clicks noisily, at a higher noise rate when the valve is open, and slows down when I turn the valve closed. This "bleeds" the air out of the system up to that point, which is adjacent to the high-pressure pump.

snip ...

Loren

My 5432 bleeder valve, which looks identical to your pictures, works the way Loren describes. I use it the same way. If you decide you need to "rebuild" that valve, Kubota or the shop that services your injectors may be able to help. They'll likely need the Nippondenso pump info off the tag that is nearly invisible, hard to photograph, and probably covered in a couple coats of paint.
 

footrope

Contributing Partner
Blogs Author
Anybody know how the injector bleed valve on the 5432 is supposed to work?

In bleeding air, I get fuel spurt from engine fuel filter, but when opening the knurled knob to continue the air bleed at the injectors, nothing happens (even while the engine is running).

This "nothing happens" was reported by several other 5432 owners. But I think my valve is broken--the knurled ring screws right off, leaving behind its axis. Isn't the whole unit supposed to turn out so fuel can spurt?

The injectors are installed and the engine starts instantly, but there's a god-awful knocking sound like we threw a rod. Mechanic friend says it's air still in system.

This photo of the valve in question is from another boat.

View attachment 22897

The knurled ring at the top should not separate from the shaft. You may be missing a set screw at the end. The shaft should turn, of course, when you turn the ring. With the little hose connected to the bleeder, you should see no fuel at the bleeder. The electric pump should send fuel there (to the injector pump) and then the hose bypasses the excess through the daisy chain of return hose that runs to each injector, etc.

How much vibration are you getting when it's knocking? If there is air in the system you should have a dead cylinder (or two?).
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Thanks all. Pretty sure from your testimony that my bleeder valve is clearly busted--corroded into two pieces.

Tomorrow I'll try removing the fuel lines from the injectors while somebody else turns over the engine (with the raw water seacock closed) to burp them.

I am told that my electric priming pump can't do this. The injector pump has to be engaged by the starter motor.

Sigh. You'd think I could bleed a diesel without "somebody else" to help....

-----

Craig

"With the little hose connected to the bleeder, you should see no fuel at the bleeder. The electric pump should send fuel there (to the injector pump) and then the hose bypasses the excess through the daisy chain of return hose"

Aha! That explains it--and the confusion in other threads. Thanks.

But of course the bleed valve has to work....
 
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Joliba

1988 E38-200 Contributing Member
Yes, Craig and Christian have it correct. I'd forgotten that when I once saw fuel at the injection pump bleed valve I had removed the hose into the return line to confirm that there was no more air. Since I haven't done this for a while it's helpful for me to have the reminder how this goes. And the mechanic is correct that fuel runs in the the pipes from the injectors only when the engine is cranking to drive the pump. Otherwise all fuel recirculates (which may be useful for polishing fuel.) For you single handers, if the engine starts on a couple cylinders it can be bled at the injector pipes while the engine is running, loosening one at a time. I saw an old mechanic do this, though I am always weary of getting caught in a moving part while working over the engine in this tight space.
 

footrope

Contributing Partner
Blogs Author
Having a helper is much easier when bleeding the injector lines, for sure. I've done it by myself, but climbing in and out without a ladder in place is some kind of exercise. A small stool helps, in place of the ladder, but I still have to step on the edge of the sink. I tied the compression release lever down with cord. It sounds like you have a good start battery.

I don't think I've read a procedure for bleeding the lines, but I bled one at a time starting with the shortest first. It may be better to crack them all and tighten them when the last one shows fuel flow. I'm not sure what a real mechanic might recommend.

When I go for the start, I usually keep the glow plugs on. That seems to help it get through the stumbles.

Remember to have fun! :)
 
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I loosened the fuel pipe connectors at the injector heads.

With Tracy turning over the engine from the cockpit, fuel spurted out.

I reconnected the fittings. The engine started immediately and ran without knocking or other signs of air.

I guess that's one easy way to bleed when other attempts fail.

I'll collect the information in a blog entry for the files.

Thanks again, fellows.

Note:

Leave it to tractor people to make bleeding obvious:

http://www.orangetractortalks.com/2008/11/how-to-bleed-kubota-fuelinjector-lines/
 
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