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  1. #1
    Platinum Member Tim_in_IA's Avatar
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    Feb 2005
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    808
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    Eastern Iowa
    Tractor
    Kubota B7610HSD, Mahindra 6500 4WD, JD 440ic crawler, 2 560 farmalls.

    Default 3 cylinder diesel engine help

    Hi,

    I picked up a Jacobsen Mower over the weekend that has a 21.5 3cylinder kubota Diesel in it. I think it is a D950. The guy said it quit while mowing and that he had a diesel mechanic look at it and the mechanic said it was an electrical issue.

    I put a new battery on it and disconnected most of the wiring. It was a mess. I am looking for what is basicly required for this motor to fire. I belive the starter switch is faulty but by providing the starter power and powering the starter relay (using my terminology here, might not be right) I can get it to crank. I haven't been able to get it to run yet. I see a white fog come out of the exhaust but it doesn't smell combusted. Just a light diesel mix. I do see a solenoid that appears to control fuel on the injector assembly with one side saying "stop", and I assume this is how the engine gets turned off but it will not run in either position. I have also checked the air filter to make sure there aren't any restrictions. Any ideas?

    Does anyone know where there is a free diagram for the wiring on this engine?
    Kubota B7610HSD, RCK60-24B MMM, LA352 Loader, Maschio 50" tiller
    Mahindra 6500 4WD ML265 Loader, 72" Bucket & Toothbar, Root Grapple, Pallet Forks, Spear
    511 Backhoe, Bushhog 296 Rotary Mower, Woods 700 blade, Jinma 6" Chipper, 3pt Spreader
    440IC John Deere Crawler
    --------------
    -Tim

  2. #2
    Elite Member Tig's Avatar
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    Oct 2006
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    2,537
    Location
    The County, Ontario, Canada
    Tractor
    Kubota, B7100HST-D

    Default Re: 3 cylinder diesel engine help

    I'm not a diesel expert but I'm comfortable maintaing and repairing mine.
    The white fog would indicate to me that at least one cylinder is getting fuel. You probably need to power the glow plugs to preheat the combustion chamber before you start the engine. 12V to the glow plugs for 30 seconds before you crank it should be enough if it's a nice day. Other than that, all the engine needs to run is compression and fuel.
    If it still won't start I would suggest you bleed the fuel system. If it's still a no go, do a compression test.
    I hope this helps.
    Steve

    The best things in life are not things.

  3. #3
    Platinum Member Tim_in_IA's Avatar
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    Feb 2005
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    808
    Location
    Eastern Iowa
    Tractor
    Kubota B7610HSD, Mahindra 6500 4WD, JD 440ic crawler, 2 560 farmalls.

    Default Re: 3 cylinder diesel engine help

    What all is involved with a compression test? Do I remove an injector and replace with a pressure gauge? I have seen the kits but I didn't know how that worked. I better just get the service manuals . If it overheated would that cause compression failure?

    Also can you tell me the proper way to bleed one of these? What should I be looking for? I see a nut on the fuel inlet. do I just bleed to that?


    Thanks!
    Kubota B7610HSD, RCK60-24B MMM, LA352 Loader, Maschio 50" tiller
    Mahindra 6500 4WD ML265 Loader, 72" Bucket & Toothbar, Root Grapple, Pallet Forks, Spear
    511 Backhoe, Bushhog 296 Rotary Mower, Woods 700 blade, Jinma 6" Chipper, 3pt Spreader
    440IC John Deere Crawler
    --------------
    -Tim

  4. #4
    Elite Member RobJ's Avatar
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    Jul 2005
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    3,482
    Location
    Spring, TX (Houston)
    Tractor
    Kubota L2500

    Default Re: 3 cylinder diesel engine help

    Sounds like you are getting fuel. how long are you cranking it, go at it for 20-30 seconds and see if it tryes to go. Put it a warm area if possible.

    My tractor is in east Texas so it doesn't get that cold, but we went up friday and I started it about 6 that evening (in the 80's). It had sat for 2 weeks and fired right up. That night we had a little cool front and I left it outside. About 9am I went to start it and the temp was around 50. White smoke and about 6-7 seconds of cranking and it kicked off. I usually don't bother with the glow plugs. But if you can get them wired they will definately help.

    Good Luck,
    Rob
    L2500

  5. #5
    Platinum Member Tim_in_IA's Avatar
    Join Date
    Feb 2005
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    808
    Location
    Eastern Iowa
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    Kubota B7610HSD, Mahindra 6500 4WD, JD 440ic crawler, 2 560 farmalls.

    Default Re: 3 cylinder diesel engine help

    I picked up a new starter switch and some new wire and ends and a wire sheild and I'll get it rewired. I'll put the glow plugs on for a decent time and hook it to the charger so it spins plenty fast and if that doesn't cut it I'll start digging into the compression and injector issues.

    On a side note, well it is related actually. On the top of the engine it has a lever. It isn't connected to anything but I notice if we move it one way or another while cranking it eases the pressure. what is this lever and what do you suppose it should be hooked to? It is near the front of the engine and comes out of the valve cover.
    Kubota B7610HSD, RCK60-24B MMM, LA352 Loader, Maschio 50" tiller
    Mahindra 6500 4WD ML265 Loader, 72" Bucket & Toothbar, Root Grapple, Pallet Forks, Spear
    511 Backhoe, Bushhog 296 Rotary Mower, Woods 700 blade, Jinma 6" Chipper, 3pt Spreader
    440IC John Deere Crawler
    --------------
    -Tim

  6. #6
    Veteran Member rdsaustintx's Avatar
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    Dec 2004
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    1,116
    Location
    Texas Hill Country
    Tractor
    Kubota BX-23

    Default Re: 3 cylinder diesel engine help

    Quote Originally Posted by Tim_in_IA
    I picked up a Jacobsen Mower over the weekend that has a 21.5 3cylinder kubota Diesel in it. I think it is a D950. The guy said it quit while mowing and that he had a diesel mechanic look at it and the mechanic said it was an electrical issue.
    Sorry, but this whole story is suspect. If a mechanic identified an electrical problem, why didn't he just fix it? All they got is a fuel pump and a stop solenoid.

    If you're not getting enough compression, you got a real problem.

  7. #7
    Elite Member RobJ's Avatar
    Join Date
    Jul 2005
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    3,482
    Location
    Spring, TX (Houston)
    Tractor
    Kubota L2500

    Default Re: 3 cylinder diesel engine help

    Quote Originally Posted by Tim_in_IA
    On a side note, well it is related actually. On the top of the engine it has a lever. It isn't connected to anything but I notice if we move it one way or another while cranking it eases the pressure. what is this lever and what do you suppose it should be hooked to? It is near the front of the engine and comes out of the valve cover.
    Sounds like a compression release for a hand crank or pull start. Typically they have a ratchet system that as the engine turns it ratchets until the release is..well released. Usually this gives the hand crank operator time to get the engine up to 5-6 turns and uses the momentum to start it. Some of them may have to be released manually. The usually hold the exhaust valve open slightly.

    Good Luck,
    Rob
    L2500

  8. #8
    Elite Member wushaw's Avatar
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    Mar 2005
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    3,075
    Location
    Bristol Texas
    Tractor
    Kubota L2800, 15 hp 372 Mitsubishi

    Default Re: 3 cylinder diesel engine help

    Get your glow plugs connected or just take a jumper and go straight to battery for a few seconds to get a little heat in the combustion chamber.

    Also do you hear the fuel solonoid clicking when you turn the key to the run position?

    Check your intake system for any cloggage since this mower is new to you just to verify you have a clear path of airflow.

  9. #9
    New Member
    Join Date
    Nov 2007
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    17
    Location
    Eastern Pa
    Tractor
    L-275 4x4

    Default Re: 3 cylinder diesel engine help

    Quote Originally Posted by Tim_in_IA

    On a side note, well it is related actually. On the top of the engine it has a lever. It isn't connected to anything but I notice if we move it one way or another while cranking it eases the pressure. what is this lever and what do you suppose it should be hooked to? It is near the front of the engine and comes out of the valve cover.
    That's the compression release. If it's in the wrong position, it won't start. You want it in the position that makes the engine harder to turn for it to start. Typically, you can use the release to get the engine to turn over quickly, then flip the compression release it to start it.

    To bleed the fuel line on my 3 cylinder, I loosen the nut where the fuel supply line attaches. Back in out a few turns, and gravity should push the fuel from the tank thru the supply line, and out the bleed.

  10. #10
    Platinum Member Tim_in_IA's Avatar
    Join Date
    Feb 2005
    Posts
    808
    Location
    Eastern Iowa
    Tractor
    Kubota B7610HSD, Mahindra 6500 4WD, JD 440ic crawler, 2 560 farmalls.

    Default Re: 3 cylinder diesel engine help

    It's alive!!!! After removing all the wiring and the old ignition switch I wired up new 10 gauge (old was 12) to the glow plugs, 10 gauge to the ignition switch, and 12 gauge to the starter solenoid and after 3 rounds of 30 seconds on the glow plugs and then turning over it finally roared! I made sure that lever on the top was set to full compression. I'll make it pretty when I have daylight again but I can go to sleep knowing it runs! Thanks guys!!!
    Kubota B7610HSD, RCK60-24B MMM, LA352 Loader, Maschio 50" tiller
    Mahindra 6500 4WD ML265 Loader, 72" Bucket & Toothbar, Root Grapple, Pallet Forks, Spear
    511 Backhoe, Bushhog 296 Rotary Mower, Woods 700 blade, Jinma 6" Chipper, 3pt Spreader
    440IC John Deere Crawler
    --------------
    -Tim

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