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  1. #1
    New Member ih574's Avatar
    Join Date
    Nov 2007
    Posts
    7
    Location
    Shenandoah Valley, VA, US
    Tractor
    International IH574, Earthforce EF3

    Default Kubota Fuel Problem

    I have a kubota D1703 3-Cylinder (in an Earthforce backhoe - same engine in an L3400 and L35). Today, it lost power and stalled. It was pretty low on fuel. So I refueled with 10 gallons of fresh fuel. Started back up but within 10 seconds was stalling again. I figured I should bleed the lines like I do in my International 574. I opened the bleed port on the Second Fuel Filter, cranked the engine, and waited till I got some spurts of fuel. I tightened the port and retried. But it still wouldn't start.

    For reference, here's the way I think the system works (Tank to Injectors):

    1. Fuel Tank Line to First Filter (course).
    2. First Filter (course) to Thing-on-Side-of-Engine-under-Injection-Pump.
    3. Thing-on-Side-of-Engine-under-Injection-Pump to Second Filter (Fine).
    4. Second Filter (fine) to Small Thumb Valve on Injection Pump
    5. Small Thumb Valve on Injection Pump to Injection Pump
    6. Injection Pump to Injectors.

    Here's what I did next. I drained the first filter (course) with a small glass bowl. Had lots of water (I think - it was clear, minimal smell, and not too oily, but I didn't taste it!). Put that back together. No start. Next I checked the line from the First Filter back to the tank. Blew air all the way to the tank. Reconnected and still no start. At this point, I couldn't get fuel to fill the First Filter nor could I get any fuel to come out of the Second Filter bleed port. Next, I drained the Second Filter. This had mostly fuel. Put it back together. Still couldn't start nor get fuel to the bleed port. I next checked each hose, blowing back towards the tank. All hoses up to the tank-side of the Thing-on-Side-of-Engine-under-Injection-Pump were clear back to the tank. When I blew back towards the tank on the Injector-side of the Thing-on-Side-of-Engine-under-Injection-Pump, it was blocked. It seems the Thing-on-Side-of-Engine-under-Injection-Pump was blocking my air pressure (mouth power through a tube).

    I reassembled all hoses and left the Injector-side hose from the Thing-on-Side-of-Engine-under-Injection-Pump open, thinking that it was a fuel pump. When cranking, still no fuel from the Thing-on-Side-of-Engine-under-Injection-Pump. That's why I am not getting fuel to the Second Filter bleed port.

    What is the Thing-on-Side-of-Engine-under-Injection-Pump? There are no electric wires to it. It seems to enter the side of the injection pump. There is a small, spring loaded lever on the side of it, but it doesn't seem to have any effect. Is it a fuel pump? A mechanical fuel cut off valve? Does a L35 or L3400 have a fuel pump somewhere else that I've missed?

    I've used a few too many words to explain this, but wanted to be as clear as I can. Thanks for any ideas or experiences with this type of fuel system.

    r-

    Tom C.

  2. #2
    Veteran Member alchemysa's Avatar
    Join Date
    Oct 2006
    Posts
    1,290
    Location
    South Australia
    Tractor
    Kubota B1550HSD

    Default Re: Kubota Fuel Problem

    I think you are correct that it is the fuel pump.

    This might help...

    Kubotabooks.com

    Look in the 'Engines' folder. Then download the 'O3 Series' manual.

  3. #3
    Veteran Member rbargeron's Avatar
    Join Date
    May 2000
    Posts
    2,473
    Location
    MA
    Tractor
    L5450, L48, L3250, L345

    Default Re: Kubota Fuel Problem

    Hi Tom - all three kubota tractors I've owned have a fuel transfer pump on the side of the main diesel pump. The transfer pump is a simple diaphragm-type pump that supplies fuel at low pressure to the main pump. A check you could do - is if the fuel tank level is a few inches higher than the diesel pump the engine may run with the transfer pump bypassed.

  4. #4
    Elite Member RobJ's Avatar
    Join Date
    Jul 2005
    Posts
    3,471
    Location
    Spring, TX (Houston)
    Tractor
    Kubota L2500

    Default Re: Kubota Fuel Problem

    I would dig up the owners manual, it'll have this in there.

    The thing on the side of the pump is the fuel transfer pump. The lever is the manual pump lever.

    Fill up your tank, put all the hoses and stuff back on. Losen the line on the transfer fuel(thing under the injection pump) pump(you want the discharge side, not the suction (fuel tank). Pump the manual lever until fuel comes out of it. If you can't feel any pumping from the transfer pump lever, bump your engine over a half turn. The transfer pump rides on a cam and if it's on the high lobe you won't get any action. When you get fuel out of the transfer pump you are almost there. Close up that line and loosen the bleeder screw on the injection pump...usually a small 10mm hex head. Pump the lever until you get fuel from there. Tighten and crank. You may have to loosen the bleeder screw again while the engine is running. Put a rag over it so you don't get a shower.

    BTW if those wonder why I loosen the line on the discharge side of the transfer pump it's because it'll clear out the air to that point a little faster. IMO.
    L2500

  5. #5
    New Member ih574's Avatar
    Join Date
    Nov 2007
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    7
    Location
    Shenandoah Valley, VA, US
    Tractor
    International IH574, Earthforce EF3

    Default Re: Kubota Fuel Problem

    First, let me say thank you to all those who responded. There is nothing better than getting advice from folks who are willing to listen and take time out of their day to provide their real world experience just to help guys like me. Thanks again.

    I went to work today and used Alchemysa's fantastic source to determine that in fact the unknown thing was a fuel transfer pump. What a great site. Then, using the part number I got from the manuals, I called my local dealer and asked if he could order one. He said yes - say the word. I told him I'd let him know tomorrow. Then, this afternoon when I got home, I read the posts from Rbargeron and Rob. Armed with that info, I went though those steps. First I filled the second filter with fuel. Next I put everything back. Then I used the manual lever on the transfer pump and (patiently) pumped until there were some bubbles showing up in the bleed port. Continuing, I got a steady stream. Next, i hooked the jumper cables back to the pickup (battery was pretty drained from all my cycling). After several tries, it stumbled to life. Within about 10 seconds, it was running smooth, responding perfectly to the throttle.

    I let it idle for about ten minutes to charge the battery a bit and get everything buttoned up. Drove the machine up to my job and worked it till done. All I have to do now is call off the dealer and possibly pay him for his trouble.

    Thanks again for your help. It is absolutely invaluable, having saved me lots of frustration and money!!

    Regards,

    Tom C.

  6. #6
    Silver Member simonmeridew's Avatar
    Join Date
    Sep 2005
    Posts
    243
    Location
    Northeastern Vermont
    Tractor
    Kubota L4400

    Default Re: Kubota Fuel Problem

    So, it sounds like the initial problem was caused by an injestion of water which blocked fuel entering the fuel injector system? Bad fuel or ??
    Then when you took it apart to get the water out of the system, there was some kind of air lock in the lines? Then it was "learn the procedure" to bleed the air out? Real good post and thread. Thanks
    simonmeridew

  7. #7
    Gold Member
    Join Date
    Nov 2005
    Posts
    475
    Location
    Colebrook, N.H.
    Tractor
    Kubota L3830HST

    Default Re: Kubota Fuel Problem

    Nothing like working through the problem to learn how your system works. I had no idea how important it is to get the system bled 'till I changed the fuel filter in our first tractor, with no manual for advice.
    -Jim

  8. #8
    New Member
    Join Date
    Nov 2012
    Posts
    2
    Location
    Vernon
    Tractor
    L3400

    Default Re: Kubota Fuel Problem

    Trying to bleed my L3400 tractor - had issue with blocked line out of fuel tank - cleared it and now tractor won't start - any ideas???

    David

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