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  1. #1
    New Member
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    Jul 2007
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    Newport, NH
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    2005 Ironhorse 284 (jinma)

    Default Idle Surge... High Idle... Eratic Idle

    2005 Jinma 284... new to me. I have no service history. 136 hours.

    Idle is eratic... sometimes idles at around 1400 rpms steady... other times it surges from around 600 up to 1400 and back to 600 and sometimes will stall. Adjusting the Idle screw does nothing except make it stall more often.

    I really need help on this.
    Thank you
    Reaney in NH
    2005 Ironhorse 284 with FEL... Soon to get more toys for the back.

  2. #2
    Super Member greg_g's Avatar
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    Dec 2003
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    6,028
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    Western Kentucky
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    JD3720 Cab, 300X loader with 4-in-1 bucket

    Default Re: Idle Surge... High Idle... Eratic Idle

    Unlike more modern diesel engines, this injection pump does NOT share lubricating oil with the engine. Perhaps it's own oil supply is low.

    //greg//
    USN (Ret)
    Former Chinese tractor owner (x4)
    Current John Deere owner

  3. #3
    Gold Member rdbigfarmboy's Avatar
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    Jan 2005
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    395
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    Collinwood, TN
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    1

    Default Re: Idle Surge... High Idle... Eratic Idle

    Its a fuel supply problem. Naturally checking hoses clamps and fittings is a place to start. The filter and or prefilter (a small screen in the supply line to the injector pump, a part of the mechanical pump assembly).
    Does it have those nice braided hoses? IF yes then you have an air leak. I have replaced half of mine. Try to twist on em or move em sometimes you cant tell. Save the banjo fitting and remove the braided hose replace with parts store fuel line and clamps.
    Anything further would be rare.
    Good luck

  4. #4
    New Member
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    Jul 2007
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    Newport, NH
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    2005 Ironhorse 284 (jinma)

    Default Re: Idle Surge... High Idle... Eratic Idle

    Quote Originally Posted by greg_g
    Unlike more modern diesel engines, this injection pump does NOT share lubricating oil with the engine. Perhaps it's own oil supply is low.

    //greg//
    It was low on oil... I topped it off... No Change on the surging eratic Idle.
    Thanks for the tip tho.
    Reaney
    2005 Ironhorse 284 with FEL... Soon to get more toys for the back.

  5. #5
    New Member
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    Jul 2007
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    Location
    Newport, NH
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    2005 Ironhorse 284 (jinma)

    Default Re: Idle Surge... High Idle... Eratic Idle

    Quote Originally Posted by rdbigfarmboy
    Its a fuel supply problem. Naturally checking hoses clamps and fittings is a place to start. The filter and or prefilter (a small screen in the supply line to the injector pump, a part of the mechanical pump assembly).
    Does it have those nice braided hoses? IF yes then you have an air leak. I have replaced half of mine. Try to twist on em or move em sometimes you cant tell. Save the banjo fitting and remove the braided hose replace with parts store fuel line and clamps.
    Anything further would be rare.
    Good luck
    Thats some great info... I will look into the things you mention. I should note... this is only a problem at idle... it runs great at higher throttle settings.
    Thank you
    Reaney
    2005 Ironhorse 284 with FEL... Soon to get more toys for the back.

  6. #6
    Elite Member RonMar's Avatar
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    May 2005
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    2,750
    Location
    Port Angeles WA
    Tractor
    Jinma 284 delivered 06/28/05

    Default Re: Idle Surge... High Idle... Eratic Idle

    I think that if it was a fuel supply issue, it would get worse at higher throttle settings due to greater fuel demand. Air in the line would cause injectors to missfire or deliver less fuel resulting in rough idle or cylinders cutting in and out.

    Unfortunatly it does sound like a governor/injector pump issue to me. The hand control you use is not really a throttle, but a speed selector. The actual throttle/rack control is moved by a centrifugal governor inside the injector pump. The spinning governor wants to close the throttle. By advancing the control lever, you are adding spring pressure to oppose the governor and open the throttle. As RPM increases, the spinning governor gains energy to fight against the spring and close the throttle again. For a given hand lever position, there is an RPM where the governor centrifugal weight is equal to the spring weight you are applying with the lever. The Jinma 200 series appears to use spinning ball bearings as the flyweights of the centrifugal governor. These press outward and force a cone shaped cup with greater and greater force as the RPM increases. Here is a page with pictures(about 2/3 down the page) of that portion disassembled courtesy of Tractor Outlet. Service Bulletin from Tractor Outlet Jinma Tractors Loaders Backhoes

    At idle, the spring force applied is light. Something such as a broken spring or spring holder could be randomizing this applied force or causing it to internally jam so the spring force cannot return to the proper low level. It could also be something with the sliding cup assembly not allowing the governor weights to come out all the way and set a 900 RPM low speed selection(idle). Lack of oil some time in it's past and excessive wear, dirt in the mechanism or poorly machined part to begin with could be interfering with this process at low RPM. Since the forces involved(spring and centrifugal) are less at low RPM, it takes less to interfere with them.
    Ron

  7. #7
    New Member
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    2005 Ironhorse 284 (jinma)

    Default Re: Idle Surge... High Idle... Eratic Idle

    Quote Originally Posted by RonMar
    I think that if it was a fuel supply issue, it would get worse at higher throttle settings due to greater fuel demand. Air in the line would cause injectors to missfire or deliver less fuel resulting in rough idle or cylinders cutting in and out.

    Unfortunatly it does sound like a governor/injector pump issue to me. The hand control you use is not really a throttle, but a speed selector. The actual throttle/rack control is moved by a centrifugal governor inside the injector pump. The spinning governor wants to close the throttle. By advancing the control lever, you are adding spring pressure to oppose the governor and open the throttle. As RPM increases, the spinning governor gains energy to fight against the spring and close the throttle again. For a given hand lever position, there is an RPM where the governor centrifugal weight is equal to the spring weight you are applying with the lever. The Jinma 200 series appears to use spinning ball bearings as the flyweights of the centrifugal governor. These press outward and force a cone shaped cup with greater and greater force as the RPM increases. Here is a page with pictures(about 2/3 down the page) of that portion disassembled courtesy of Tractor Outlet. Service Bulletin from Tractor Outlet Jinma Tractors Loaders Backhoes

    At idle, the spring force applied is light. Something such as a broken spring or spring holder could be randomizing this applied force or causing it to internally jam so the spring force cannot return to the proper low level. It could also be something with the sliding cup assembly not allowing the governor weights to come out all the way and set a 900 RPM low speed selection(idle). Lack of oil some time in it's past and excessive wear, dirt in the mechanism or poorly machined part to begin with could be interfering with this process at low RPM. Since the forces involved(spring and centrifugal) are less at low RPM, it takes less to interfere with them.
    Thanks for that great explaination. I'm going to tear down the governor next week and see whats up. Worse case is I order a new pump. My "great deal" is evaporating fast. LOL
    It looks to me like I can access the governor without removeing the entire pump. so it shouldn't be to bad.
    Thanks for the help.
    Reaney
    2005 Ironhorse 284 with FEL... Soon to get more toys for the back.

  8. #8
    Gold Member rdbigfarmboy's Avatar
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    Collinwood, TN
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    Default Re: Idle Surge... High Idle... Eratic Idle

    The speed governor is fairly simple. It could have a bad bearing.
    Im still with it being a fuel supply problem. The mechanical pump is fairly week and is part of that screen mechanism. Is there any wet or thick dust around the injector pump, supply lines, or mechanical supply pump. at all?
    Good luck

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