Engine will not run with bleeder screw closed.

dchimirev

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L245
Aug 22, 2017
24
3
3
Putnam Valley, NY
I got a V1902 4cyl diesel. It runs with the bleeder screw open, but dies soon after I close it. This is the little thumb screw that's on the injection pump that from I understand is only used to purge the system from air. What could be the reason for this? Could it be that I'm sucking air somewhere between the tank and the injection pump? (there are rubber lines, an in-line filter, and a lift pump). What else could be the cause? Thanks.
 

RalphVa

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Jan 19, 2020
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We had a 240D Benz that we had for 25 years. At one point, the rubberish fuel line to the small filter developed some radial cracks that sucked air. It was so bad that it would not run but a second or two. In your case, maybe there's just a tiny bit that the bleeder screw releases.

Replace the short line, and everything was fine, but also replaced the same kind of line from the fuel tank.
 

PoTreeBoy

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I got a V1902 4cyl diesel. It runs with the bleeder screw open, but dies soon after I close it. This is the little thumb screw that's on the injection pump that from I understand is only used to purge the system from air. What could be the reason for this? Could it be that I'm sucking air somewhere between the tank and the injection pump? (there are rubber lines, an in-line filter, and a lift pump). What else could be the cause? Thanks.
We don't know the particulars of your engine, but I'm wondering if there is an obstruction in your normal flow and your injection pump is drawing back through the purge valve?

Remove the fuel feed line at the injector pump and see if you get a good stream of fuel with the lift pump running (electric or mechanical)?
 
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North Idaho Wolfman

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Bad lift pump is #1, Bad seal on the filter assembly #2, Bad fuel lines or bad return lines #3.
 
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Torinodan

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Can I ask why a bad return line would effect anything? My understanding is that once the fuel goes past the injectors, it should not effect how the motor runs? I'm guessing i'm wrong, but don't know why
One of my G4200s had a crushed spot in the return line and it didn't like running at and rpm over idle. It was completely pitched where a rock or limb hit it next to the frame and wasn't easy to find.
 

Henro

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B2910, BX2200, KX41-2V mini Ex.
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Haven't had a chance to fix the issue, have been running it with the valve open for now.
I don’t have an answer but there must be a message in the fact that you are running the tractor with the bleed valve open. Are you losing fuel out of the bleed point when you do this?

I would expect you should be.
 

North Idaho Wolfman

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Can I ask why a bad return line would effect anything? My understanding is that once the fuel goes past the injectors, it should not effect how the motor runs? I'm guessing i'm wrong, but don't know why
Bad / Plugged return line will cause the injectors to over pressure and pop too fast.
 
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dvcochran

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Kubota M9000, New Holland TN90, Deere 2640, Vermeer 504N, Vermeer 504SI, more
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Dickson, TN
I got a V1902 4cyl diesel. It runs with the bleeder screw open, but dies soon after I close it. This is the little thumb screw that's on the injection pump that from I understand is only used to purge the system from air. What could be the reason for this? Could it be that I'm sucking air somewhere between the tank and the injection pump? (there are rubber lines, an in-line filter, and a lift pump). What else could be the cause? Thanks.
I have an old Scat Trak skid steer with a V1902. Tank of a little engine but finicky on fuel supply. There is no supply pump (just a primer), and they rely on super clean lines, tank, and filter to get enough suction fuel.
I have seen the situation like you have where cracking the bleeder screw allows the machine to run. My best guess is with the bleeder screw open there is enough 'atomized' fuel to allow the machine to somewhat run but not enough to do any work.
My old Scat Trak does not move very often. When it does not want to start. I run new fuel line and replace the filter. While the filter is off, I make sure there is good flow from the tank. So far, this has fixed my problems. It does sound like you will have to bleed the injection lines out. That can be a little tougher. If it ever bumps, I Very Sparingly use starting fluid. Remember, while these are older machines that are more tolerant to starting fluid, they are not bulletproof.
If your machine does run regularly, always add some algaecide like the white/green label bottle of Power Diesel Services.
 

dchimirev

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L245
Aug 22, 2017
24
3
3
Putnam Valley, NY
Solved. Dry rotted rubber fuel line that was letting air into the system.

Thank you all for your input. After trying all the suggested solutions and not being able to resolve the problem I was left with just one more thing I could try: replacing the last bit of rubber fuel line (from the tank to the lift pump). I had been holding off doing this because the body work and oil lines were completely blocking access to the hose clamp that I'd need to open to take the line off. Long story short, after putting an angle grinder to the body work, I got the rubber line off and it was all dry rotted and cracked, so that was the source of the air getting into the system.
 
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Henro

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Glad you got it fixed!

Still can’t understand why you were able to run and use the tractor only with the bleed screw open though…guess it has to be that the air that the lift pump was sucking was somehow being expelled through the bleed screw.
 

RBsingl

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Kubota F 2690 72" rear discharge deck, Deere 955
Jul 1, 2022
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I suspect that dry rotted line was partially blocked and collapsing under suction. With the bleed screw open, the pump wasn't able to create enough suction to cause the line to fully collapse so it pulled enough fuel, probably mixed with some air, to let the engine run.

Collapsing rubber hoses can create a lot of issues like vehicles that overheat when the lower radiator hose gets old and collapses and brakes that stick because the collapsed line doesn't allow the brake fluid to return from the brake pistons. Glad the OP found the issue!

While waiting (and waiting and still waiting) for my Kubota F2690 to be delivered, I downloaded the operator manual and bought the WSM for it. Kubota calls for the fuel line to be replaced every 2 years when using biodiesel blends which is pretty much all diesel fuel sold in the U.S. for years. I am not planning on replacing fuel lines on a regular basis (normally they call for every 4 years when not using bio blend) but it does show they expect fuel lines not to last forever.

Rodger
 
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galstaf

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B26
Sep 27, 2018
18
0
1
Stone Mountain
Bad / Plugged return line will cause the injectors to over pressure and pop too fast.

Hey Wolfman (and everyone!) , I have an ongoing massive PITA issue with a B26 kubota. It runs fine a lot of the time, then will randomly just start chugging and dying, and it will be a bitch to restart.. run for a few minutes or a few seconds or occasionally 30 minutes and then stall and die again.

I have done everything I can think of:
  • Drained and cleaned the tank
  • I have put 2 inline fuel screens before the factory filter so I can see when there is fuel in the system.
  • I thought the fuel pump itself was dying, so I added a switched 12V fuel pump *after* the fuel filter but before the mechanical lift pump the tractor uses. If I leave it running, it seems to overwhelm the system and causes the tractor to stall, however I switch it on to help restart after one of these stalling conditions occasionally. Not needed most of the time.
  • I have tried the injector cleaner additives, and even pouring the injector cleaner into the air intake. This did seem to clear a bunch of gunk out.. lots of carbon bits came out of the exhaust, but it did not fix the issue.
  • I thought it may be the tractor "safety switches" that stall the tractor if you stand up, or try to move with the seat backwards, etc. There were 5 potential switches that could cause a stall. I have bypassed the entire system at this point to remove it as a possibility .. so none of those switches do anything anymore. I can stand up and move the tractor, move with the seat backwards in BH mode, etc.
  • I assume if the injectors are blocked in some fashion it would be a constant issue.. like constantly not starting or constantly running like crap, not this seemingly totally random bizarre symptom.
The bottom line is that the injectors are getting plenty of fuel delivered. Because it is so intermittent and random it is infuriating. I have had a couple of techs come look at it and of course the tractor won't do the stall thing if there is someone else there who could potentially fix it. It seems to happen when it's hot, when it's cold, under load, no load.. driving fast or barely moving.

So further reading lead me to look at fuel return lines. I noticed mine had a bit of surface crazing on the rubber but were not leaking.
I sent the wife off to get me to matching rubber hose, put it on, and like magic it ran like a champ for the rest of the day! Problem solved? oh hell no!
A week of running great then back to the same random issue.
I reset the lines and noticed the Autozone had given my wife vacuum hose line, which I suspected was not fuel rated.
So took all that off, and got some fuel rated line from O'Reilly's (the only store locally that had anything close to the correct diameter).

Again.. seemed to run fine for a while, and is seemingly a lot better than before, but it is still acting up.
So I wondered if anyone could help answer the following:
  1. Do the fuel return lines have any "inherent pressure" or do they just take excess fuel and drop it in the tank? (The reason I ask, is that it seems the stalling got worse when the new fuel line had worked loose from the nipple going back into the fuel tank). Again, given how random it is, it is hard to determine correlation vs causation.
  2. Can the fuel return lines be removed completely theoretically? I realize this will dump diesel all down the engine, but my question is linked to number 1 above. Do the fuel return lines have any back pressure requirements. If they are letting a little air in at a splitter, would that cause the stalling issue
  3. Is there anything special about the OEM fuel return lines that I should consider? Even tho I have brand new fuel rated rubber tubing on the whole system, is there something the Kubota lines would make different?
I feel like I am missing something simple. When the tractor is running well (which it will often do for a couple of hours at a time) all is good, so the injectors, pump, etc etc have to be working right, correct?
Is there anything else that would cause this randomness? Some sort of heat or level or pressure sensor perhaps?
It is driving me crazy... so if you can do anything for my tractor and mental health, I would really appreciate it!!


Please help!
 

North Idaho Wolfman

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No pressure on the return lines.
I think your barking up the wrong tree, it sound to me like you have an issue with the stop solenoid.
It will do everything you mention.

On a side note
  • I have tried the injector cleaner additives, and even pouring the injector cleaner into the air intake. This did seem to clear a bunch of gunk out.. lots of carbon bits came out of the exhaust, but it did not fix the issue.
OMG....
So knowing you did that, I would say do a compression test and have the injectors tested!
 

galstaf

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B26
Sep 27, 2018
18
0
1
Stone Mountain
No pressure on the return lines.
I think your barking up the wrong tree, it sound to me like you have an issue with the stop solenoid.
It will do everything you mention.

On a side note
OMG....
So knowing you did that, I would say do a compression test and have the injectors tested!

I did actually talk to the tech department for the cleaner (I wanna say seafoam?) to see if that was OK on a diesel. It is designed for that use. (cleaning injectors/decarbon cylinders)

Also, if the injectors / compression were shot, surely it would be consistently flaking out, no?
 

galstaf

New member

Equipment
B26
Sep 27, 2018
18
0
1
Stone Mountain
No pressure on the return lines.
I think your barking up the wrong tree, it sound to me like you have an issue with the stop solenoid.
It will do everything you mention.
I did consider the Stop Solenoid. I actually have a volt meter on the stop solenoid to make sure it isn't losing power intermittently. Plus it makes a pretty resilient clunk when the solenoid disengages, so I would hear it. Also when the stalling occurs, it kinda dies slowly over a few seconds. .. coughing and spluttering. If the stop solenoid kicks in, the engine is killed immediately.

Is there possibly another sensor, or a computer or something/anything else that may cause this?
 
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