How to Bleed Kubota Fuel Injector Lines

Sooner or Later…
It’s not a matter of if you’ll ever have to bleed the injector lines on your Kubota, it’s quite simply when. Throughout the course of regular maintenance this procedure will come up a few times and you’ll be prepared to pull this basic service job off with these tips.

Why is Bleeding Necessary?
Bleeding the injector lines is necessary when you’ve run out of fuel, or have changed a fuel filter and have introduced an air gap into an otherwise closed system. This air gap will prevent fuel from getting to the engine and will stall your equipment – not good. There are two methods to bleed this system, one using the bleed valve and cylinder head decompression, and the other involves loosening the injector lines from the injectors. Either method is a straightforward procedure.

Bleed Valve and Cylinder Head Decompression
The first method purges air between the fuel filter bowl and the injector pump. This air lock is what commonly occurs whenever a fuel filter has been changed. Open the fuel bleed valve located on the side of the injection pump by rotating fully counter-clockwise.

Open fuel bleed valve on side of injection pump by rotating counter-clockwise

Open fuel bleed valve on side of injection pump by rotating counter-clockwise

Next pull on the cylinder head decompression knob to decompress the engine and relieve any cylinder head compression. This photo shows the cylinder head decompression lever with the cable pull removed for clarity – ordinarily you have a knob on the dashboard and that cable attaches to the lever shown below. By relieving the compression, the engine will crank over much faster because it’s not fighting that compression which cycles the injector pump and because the fuel bleed valve is open, the line will clear of air.

Pull on the cylinder head decompression lever and crank the engine for 10-15 seconds

Pull on the cylinder head decompression lever and crank the engine for 10-15 seconds

Crank over the engine for 10-15 seconds, close the fuel bleed valve and attempt to start the tractor as you would normally do (don’t forget to preheat your glow plugs).

Bleeding to Top of Injectors
If your Kubota fails to start, then you’ll need to bleed the lines all the way to the top of the injectors themselves. To do this, locate the injector lines and notice where they enter the top of the injectors.

Locate injector lines on top of injectors

Locate injector lines on top of injectors

Your Kubota tractor will have either 2, 3 or 4 injector lines and all of them will require have to be burped. Using a 17mm wrench (everything is metric on a Kubota), loosen the nut holding the injector line into the top of the injector.

Loosen all injector lines from the injectors using a 17mm wrench

Loosen all injector lines from the injectors using a 17mm wrench

With these nuts well backed off, grasp the injector line and tug upwards on the line to disengage the steel line from the top of the injector. Once you’ve unseated all the injector lines, open the fuel bleed valve on the side of the injector pump (as discussed above), pull on the decompression knob to relieve the cylinder head of any compression, and then turn the key and crank over the engine.

While cranking the engine over, watch for diesel fuel to spurt out of the ends of the loosened injector lines. When you can clearly see evidence of fuel spitting from each line stop cranking the engine, close the fuel bleed valve, release the decompression knob, and tighten up the nuts holding the injector lines. Once tightened, congratulate yourself on bleeding your Kubota Tractors injector lines!

Every Kubota tractor owner will run eventually run the engine right out of fuel. Sometimes that fuel guage just isn’t big enough!

Service Department Vic

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Forum: Service, Repair & Maintenance


  1. Debora Said,

    November 30, 2008 @ 2:54 pm

    This was very helpful even though I was looking for a diagram of how the fuel injectors go together. Once we got the injectors put together correctly, however, this was a very thorough description of bleeding the fuel injectors — much better than I have seen before and having both text and pictures and video was awesome! Thanks so much for providing this information.


    Debora & Stephen

  2. roserail Said,

    December 20, 2008 @ 9:11 pm

    Hmmm. could have saved myself a lot of grief if I had found this earlier.
    A new question. I have a B1600 DT with rototiller and an after market front loader. I have hydraulic power to the loader and the tilt adjuster on the rototiller but the “3 point hitch” arms do not. oil level is good and I do not see any obvious leaks. Any ideas?

  3. Vic Said,

    December 22, 2008 @ 12:55 pm

    Hi Brent,

    I should have you upload a picture of where the hydraulic lines (probably rubber hose) leave the tractor and go to the loader control. We have that ability on our site, under Kubota Gallery.

    There may be a directional control valve installed just downline from the tractors hydraulic pump, as is the case on factory installed Kubota loaders.

    When the direction valve is turned “in line” (90 degrees away from the tractor body) with the hoses that lead to the loader control, then only the front end loader will work, the 3 point hitch will not.

    When the direction valve is turned parallel to the body of the tractor, fluid will still enter the control valve to operate the loader when demanded (operated), otherwise the hydraulic fluid travels “beyond” the loader control valve to make pressure available to the 3 point arms when demanded.

    The hydraulic arm on the 3 point operates off a seperate output source taking residual hydraulic power independant of the 3 point or loader which is why it works.

    Since this is an aftermarket loader, it is possible that the loader control valve (up-down, tilt-rollback) or plumbing on the hoses is incorrect. Sketching a diagram and uploading can assist us in helping you diagnose this repair.

    Your tractor is designed to operate on an “open centre” basis.

    This means that hydraulic power flows “through” the loader control, and onto the 3 point hitch. Power is available for operating the loader when needed, and is there for the 3 point when needed as well.

    Let us know how many hoses or lines enter and leave the loader control valve and where you think they go. Your Kubota will have either 2 or 3, not including the 4 lines or hoses that operate the front end loader hydraulic cylinders.

    Service Dept Vic

  4. Lewis Said,

    December 27, 2008 @ 4:14 pm

    Hello Vic
    I have no idea if this is the correct place to ask this question but I just saw your site and thought that I’d give it a try. I ran out of fuel (or so I think) on my b6000 a few days ago. I have bled this system repeatedly with no sucess. While trying to diagnose the problem I have began to suspect the electric (lift) fuel pump. This is a pump on the left side of the tractor just under the battery. There is 12v going to this pump but it does not seem to pump any fuel. When I rest my hand on this pump and turn on the ignition there is no vibration or noise. I believe that it is bad. Can this be replaced with any (NAPA etc.) electric fuel pump? If so what kind of pressure and GPH is required. Thanks

  5. Vic Said,

    December 28, 2008 @ 1:58 pm

    Hi Lewis,

    There are 3 places to bleed to eliminate all the air from the B6000. There are 2 places on the upper part of the fuel filter, and one on the upper part of the injection pump. If you have bled the system right to the top of the injector lines as we detail on this segment, then it sounds like you’re on the right track to consider the fuel pump.

    However, before you go replacing that pump verify that it’s got a good ground source. While the electrical system on your Kubota is very basic, a lot of issues with it are related to a poor ground (negative) source.

    Run a jumper wire from the battery directly to a good ground source on the pump and then see if the pump activates. If it doesn’t there may be another reason for it, read on!

    That pump is still a current Kubota stocking item, the part number is 68371-51210, prices around $95USD. We’re advocates for using correct replacement parts as they fit, work, and are designed to work in harmony with your tractor.

    Kubota indicates a discharge on that pump at 500cc’s discharge side up. Normal working voltage is 8-16V and average current consumption at 08A.

    Here’s how that pump works.

    The “working” part of the pump contains a piston and valve located in the centre part of the pump. A coil winding encompasses it. When 12V current is turned on, a magnetic field is formed in the coil causing the piston to “release” which in turn discharges the fuel. When the piston reaches it’s upper limit of travel the 12V current is cut off and the piston is pushed down by the force of an internal spring. This action is repeated over and over again forcing fuel to flow in the direction of the injection pump.

    It is quite possible that the internal piston in the fuel pump is stuck in the upper most range of it’s travel. The 12V power to it would be bypassed, and the internal spring may not have sufficient potential energy to drive the piston back down and turn the power back on!

    Try removing the pump and mabey submerege it in a good parts cleaner, try an air pressure hose on it to see if you can free up that piston, and see if any crap, rust and scale comes out of it.

    I would further speculate that an aftermarket replacement pump should you decide to go that route may have more output than you require from the factory pump.

    Let us know what you find out by posting a follow up!

    Service Dept Vic

  6. Lewis Said,

    January 1, 2009 @ 3:15 pm

    Hello Vic
    Thanks for the reply though I wasn’t able to respond till now and have since replaced the fuel pump with a Facet model bought at a local auto parts store. My local Kubota dealer was able to get a replacement pump but it was a few days away and I had to take care of the snow on my driveway so I went with the Facet and it seems to work well. The clicking sound brings back memories of an MG I once had. I’m guessing that electric fuel pumps haven’t changed much and that the Nipondenso that was on this tractor wasn’t working since I have never heard it click in the four or so years that I have had this B6000. If you don’t mind addressing another question: I am currently plowing the snow off my driveway with a backblade and my FEL. This usually works pretty well and given my situation the FEL is useful for removing he snow. A friend has offered me a six ft. plow blade with manual angle that he isn’t using. This was used in the past by him with a compact Kubota. He now has a larger tractor and a bigger plow. He describes this blade as hooking over the FEL bucket and being secured by a chain to the hook on the top of the bucket. Apparently easy on and off. I haven’t seen it. What do you think of this? Will the B6000 handle a six ft. blade? Am I risking damage to the lift arms? Thanks for the help.

  7. Vic Said,

    January 3, 2009 @ 9:32 pm

    Lewis, glad to hear that your fuel delivery situation is handled!

    I have no spec for blade size on the front of a B6000, but my instict is telling me it’s a little too big.

    Ask your friend if you can “demo” it, see how it performs. I suspect you’ll find that B6000 to be underpowered when using a front blade, and the extra weight up front may take away some traction. Let us know how it turns out, mabey post a picture to our gallery page of the blade mounted on your B6000.

    Service Dept Vic

  8. Charlie Said,

    March 19, 2009 @ 2:56 pm

    Hey thanks – just started my old DT2000 by following the instructions and watching the video!!! Wish I knew this a few years ago (yes – I have run my tank dry a few times @#$%!) – would have saved hours of cranking while spraying WD40 in the air filter (which worked). THANKYOU FOR POSTING THIS INFORMATION/VIDEO.

  9. Mr. K Said,

    March 19, 2009 @ 3:46 pm

    Hey Charlie – happy to help out! Gotta work on keeping your tank topped up I guess. :)

  10. Glenn Said,

    April 6, 2009 @ 12:36 pm

    Hi Vic,
    I followed the instructions for my -05 L3130. I am not getting fuel to the injectors.
    I have fuel at the pump.. cranked for about 5 min total 10-12 sec each time.
    Could there be another issue

  11. Glenn Said,

    April 6, 2009 @ 12:38 pm

    Hi Vic,

    Fuel problen addendum
    Maybe it would help to tell you that the -05 L3130 sat for 2.5 years.

  12. Glenn Said,

    April 6, 2009 @ 2:26 pm

    Hi Vic

    I have followed the directions on my L3130 ,2005
    I turned the engine over for about 5 min total, 10-12 sec intervals,
    I’m not getting any fuel to the injectors. The tractor sat for two years.
    How long does it take to filll up to the top of the injectors

  13. Vic Said,

    April 7, 2009 @ 9:17 pm

    Glenn, check to make sure that fuel will gravity flow from the tank to the fuel bowl. Bleed the injector pump by opening the bleeded or it. make sure fuel spits from there. Then move on to bleeding the injector lines. You may want to verify that the fuel lift pump is also working by disconnecting the hose exiting it to see if fuel flows when cranking.

    It takes just a few revolutions of the engine to charge the lines with fuel.

    service Dept Vic

  14. Glenn Said,

    April 8, 2009 @ 4:01 am

    Hi Vic,
    I’m a little confused, What does this mean “Bleed the injector pump by opening the bleeded or it.”
    Where is the Fuel lift pump located “verify that the fuel lift pump is also working by disconnecting the hose exiting it ”
    Thanks a lot for the help

  15. Vic Said,

    April 8, 2009 @ 8:37 pm

    Glenn, I’m a fat fingered idiot! Supposed to say, “Bleed the injector pump by opening the BLEEDER on it”!!

    Ok, lets get the obvious out of the way here first! Make sure that the “Engine Air Kill” knob pushed back “in”, and is not in the “out/stop” position. If it’s left in the out/stop position you’ll crank that Kubota all day and it won’t start!

    Here’s a trouble shooting plan to bleed the injectors and fuel delivery system on that L3130.

    The bleed screw is located on the injection pump block just below where the centre injector line is located.

    Located on the bleeder, is a banjo fitting with a rubber fuel hose, that will trace back 6-10 inches or so, on the same side of the engine block to the fuel lift pump.

    The second line comming from the fuel pump will trace back to the fuel filter bowl.

    There are three fuel lines hooked up to the fuel filter bowl. One comes from the tank, one goes to the fuel pump, and one is a vapor return to the upper part of the fuel tank.

    Loosen off the retainer ring holding the fuel filter bowl in place, so fuel washes over the sides of the plastic cup. Tighten it up, as the fuel is flowing to eliminate an air lock on “top” of the fuel filter. Next, disconnect the fule line comming from the fuel filter bowl, into the fuel pump. Confirm that fuel flows there. Reattach, and then disconnect the fuel hose comming from the fuel pump to the banjo fitting at the bleed screw on the injector block.

    Crank the engine and verify you have fuel comming from the fuel pump. Then, reattach the hose, and loosen off the three 17mm nuts holding the steel injector lines to the top of the nozzles. Loosen a few good turns, and pull up on the lines to “un seat” them. Crank over the engine to ensure that you have fuel at the top of the injector nozzles.

    Let me know what you find out!
    Service Dept Vic

  16. Glenn Said,

    April 9, 2009 @ 4:09 am

    Hi Vic
    I don’t see any “Engine Air Kill” knob. Where would I find that ?
    I’m going to go through the process this weekend, Thanks

  17. Ian Said,

    June 6, 2009 @ 2:25 pm

    I have a Kubota M110 sitting in my yard that will not start. It ran fine last week, but today it won’t turn over. When turning the key in the ignition, all the display lights light up OK, then you hear a faint “click”. The engine does not turn over at all. Any suggestions out there??

  18. Vic Said,

    June 7, 2009 @ 9:06 am

    If I was on that Service Call, I’d start checking battery terminals, ground cables etc. Basics, basics, basics on electrical issues!

  19. Ian Said,

    June 7, 2009 @ 11:39 am

    I’ve checked the battery terminals and battery and all is OK. I’ve also checked all the cables around the starter and they are all tight and look OK too. I can hear what sounds like a starter relay pick up when the key is engaged to start, but the starter motor will not work. I’ve checked the fuses too.

  20. Ian Said,

    June 7, 2009 @ 4:08 pm

    Vic, do you think it could be the solenoid??

  21. Vic Said,

    June 7, 2009 @ 4:33 pm

    Mabey. Are you able to use a jumper wire/cable to see if it will engage?

  22. Ian Said,

    June 10, 2009 @ 12:51 pm

    Thanks Vic, I figured out what was wrong. The 3 point raise lower switch was not down all the way, and I guess this prevented the machine from starting. Some sort of safety measure I guess. I’m new with this tractor……never had one before. Thanks for all your help.

  23. Nick Vrolyk Said,

    August 4, 2009 @ 8:46 pm

    Hi Vic,
    I have a Kubota 245DT that I bought new in 1976. I use it every few months mostly mowing the weeds with a 5′ rotary mower off the 3 pt hitch. Lately I have not been getting the power that I usually have this seems to be intermitent. It will seem to be running on all three cylinders and then it will just slow down to a crawl at full throttle.
    Can this be a bad fuel injector?
    It is also difficult to get the glow plugs to warm up when I first start it. Will it help to replace the glow plugs?
    I do not think I have had them or the injectors replaced since it was new.
    I also have a starter clicking problem where the starter just seems to take forever before it will engage the flywheel.

  24. Vic Said,

    August 6, 2009 @ 6:44 am

    Sounds like it’s time for some maintenance Nick! It’s doubtful that you have a bad injector since the performance issue is intermittent. It may be as simple as a fuel starvation issue from a dirty fuel filter. How do you know the glow plugs are not working? Have you removed them and bench tested them? Starter issue sounds like a corroded cable or poor ground contact. A Saturday afternoon and a good detailed maintenance service job should resolve your issues. At the very least, it will provide you with a good basis for further diagnosis.

  25. Patryk Said,

    August 8, 2009 @ 1:47 pm

    Hello. I buy a Kubota B1600 tractor , and I want change the oil in the engine, but I dont know how liter the oil i must fill on the engine- please tell me, thanks for answer :)

  26. John Said,

    September 24, 2009 @ 7:06 pm

    I have a m8200 kubota tractor that when running the pto at 540 rpm (bush hog) will act like it is starved for fuel. It will idle all the way down with the throttle still up. Sometimes it kills the engine. I changed the fuel filter. What else could it be? Any ideas would help greatly. Thanks.

  27. Rich Said,

    November 21, 2009 @ 8:35 pm

    Hi, I have a B6100 that is getting diesel fuel into the crankcase oil and I’m wondering how this is occuring? I keep changing the oil and trying to remember to shut the fuel off when it’s not running, but I didn’t used to have to do this. Can you help me? Thanks, Rich

  28. Service Dept Vic Said,

    November 22, 2009 @ 9:29 am

    You’ve got bad injectors. Rebuild or replace!

  29. Rich Said,

    November 22, 2009 @ 10:21 am

    Where can I buy these? Would it be the pump? or just the 3 injectors? Thanks, Rich

  30. Vic Said,

    November 22, 2009 @ 10:50 am

    Would be the injectors. Think of them like a “tap”. They are designed to “snap” open when a specific pressure is acheived. If the tip gets dirty or corroded with junk, it will remain partially open, leaking fuel causing diesel to wash into the crankcase. Personally, I would remove them, mark their location to make sure you re-install in the same place, and disassemble and clean each one. They will be “tight” so use a good quality socket and wrench when taking them apart. don’t loose anything, and reasseemble in the exact same order. Pay attention to the pintle tip area, this is where your problem will be. If you drop one of the injectors when it’s out and it hits the exposed tip, you’ll be replacing all three with new ones. Wash them out well with carb cleaner and a small bottle brush, make sure they are clean as a whistle.Re-install and see if that doesn’t solve your problem first. If you desire, once cleaned, take the injectors to a local diesel shop and have them check the spray pattern and opening pressure. They’ll be able to tell you in a second if they require replacing based on that pressure test.

  31. JAIME ROSA Said,

    December 3, 2009 @ 9:20 am



  32. Vic Said,

    December 3, 2009 @ 11:24 am

    Jamie, repost this question into the forum area for the benefit of all and we can answer your questions there!

  33. Dennis Said,

    December 10, 2009 @ 11:47 pm

    I bought a used Kubota 245dt 20 years ago from a local campground. When I use it, I work it hard all day long – moving dirt, grading roads, mowing with 3 point mower deck. However, between uses, the tractor is parked for weeks or sometimes months. I do not know how many hours are on the 3 cylinder diesel motor. This old tractor (1978?) starts easy and does a lot of work.
    My problem:
    A steady stream of smoke is pumping out of the breather pipe on the side of the engine. It’s really bad at idle or low engine rpms. When the motor is working really hard the smoke is not as bad. I change oil/filter frequently, which helps for about a day. I’ve never touched the injectors. Do you think the rings are shot?

  34. kent Said,

    December 27, 2009 @ 7:55 pm

    Vic, I have an older M7030 utility in a remote location with no dealer assistance available. I think it is a 4 cyl V4000 engine but not sure. I acquired the unit over the phone and later discovered that the previous owner could not get it running either. I have bled the air going to the injection pump but the injection pump will not push fuel to the injectors. The strange thing is that the unit tries to start(presumablly on the one injector that I cannot access with the wrench that I have). I have had the top cover off the injection and everthing looks clean and no evidence of water in the top of the pump. There does not appear to be a bleed screw for the pump itself. Pump plate says that it is a Mccuni precision CAV 503 1000 672590/0979AN 73942F533. I am told that one of these numbers is actually a J but pump guy would not say whether it was the 5 or the 7 that I misread. This tractor has teased me on two seperate occasion when I make the long distance trip to get it started. The fuel injection rebuilder says that it is probably low compression causing the (does not start condition) but I contend that that my be but first I must get adequate fuel to the injectors before I start pulling the engine apart. Any ideas. Thanks for the taking the time to read this. kent

  35. Paul Said,

    January 9, 2010 @ 5:18 pm

    I have a Kubota V2203 engine that has water at the injectors when I bleed them. I know I have to drain the tank, lines, and replace the filter. What do I need to do to get the water out of the injector pump, lines and injectors?

  36. Bryan Said,

    January 31, 2010 @ 11:31 am

    I have a Kubota B2100, Ive heard a lot about this decompression knob and cant seem to find it. I have bled the injectors without success of it starting. It just turns over and coughs like it wants to star here and there. I replaced the fuel filter and still no luck. HELP.

    Thanks, Bryan

  37. chet Said,

    February 4, 2010 @ 12:45 pm

    I was running my tractor it a L3130 at about 3/4 throttle pushing snow shut it down to put more fuel in and then it would not run any higher than 1200 rpm Ihave cleaned the fuel lines changed the filters dont know what esle it could be any thoughts.

  38. chet Said,

    February 4, 2010 @ 12:48 pm

    Sorry that was a Kubota L3130

  39. David Said,

    July 27, 2010 @ 8:03 pm

    I snagged the fuel line and split it and lost the fuel load. Turning the key won’t crank engine. Is this normal for a fuel line failure? Kubota 3400 with 12 hours!

  40. Vic Said,

    August 4, 2010 @ 7:49 pm

    Nope. You’re missing something. The tractor is in gear, the clutch is not depressed, the mower deck is still engaged, some safety interlock is active. Check your machine over, you’ll find it!

  41. Pam Boyer Said,

    August 9, 2010 @ 7:20 am

    My grandaughter let my Kabota la853 run out of diesel. I have read the directions and, I’m going to try to do it. What is the little pump like thing on the left side of the air filter. Right in frount of the tractor? I seem to have lost the manual that came with the tractor?

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