Dense black smoke plume - new John Deere diesels

Discussion in 'Diesel Engines' started by Richard O, Aug 4, 2008.

  1. Richard O
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    Richard O New Member

    I am in the late stages of commissioning a new trawler (126,000 lbs. displacement) equipped with dual John Deere 6068SFM-50 diesels; 267 hp. The engines are new - approx 40 hours total.

    Propellers are 32” diameter; 24.5” pitch; four blades - and have been used successfully on similarly configured boats.

    The engines run well and smokeless in general operation.

    BUT, when put into gear and quickly but briefly powered up - for example to generate a brief burst of power during docking - they emit a very, very dense, black plume of smoke from the exhaust.

    This has occurred when the engines were hot (after running for a couple of hours, though at low power settings for the 30 minutes or so prior to the docking). It has also occurred with the engines only slightly warm at the dock (an experiment to test for the smoking condition).

    The John Deere service center says this is normal and just advises to be less aggressive with throttle action. I fully understand that especially with turbo-charged engines, aggressive throttle action is not desirable. However, this condition was first observed during normal docking operations with a very experienced professional captain at the helm. The throttle action was not abnormal. My prior experience is with CAT-3208 TAs and I’ve never seen anything like this.

    I have attached a video showing the smoke plume but beware: it is 2.9 MB.

    So, two questions: first, what is the cause of the smoke plume and, second, is it (as the JD tech says) a normal condition?

    Any help would be appreciated.
     

    Attached Files:

  2. Landlubber
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    Landlubber Senior Member

    As these are electronically controlled engines, there must be a computer malfunction of some sort, there is no way known electronic engines should do this. In fact when ther are abused by the throttle opening, you cannot tell anyhow, as the sensors take over and reduce fuel inputs to suit.

    I think that you had better get the JD tech boys onto it. You need the laptop setup to see what has failed and where.
     
  3. lazeyjack

    lazeyjack Guest

    yes are they tier 2?
    no modern diesel will do that, even if you are overproped
    look at this way, an analogy, a truck, driver to lazy to shift at a hill, buries boot, , there should not be a cloud of smoke at all . Just so happens before I started building boats in 78 i was a field service engineer for Cummins, so I got to know about fueling
    Dont be put off you ARE under warrenty, get those people down!! Are you sure they are not Jap diesels:) black smoke is unburnt fuel, which comes from over fule, or turbos not working, As Lubs says it maybe a engine management electronic issue
    Our new design has the 4 cyl tier 2 motor
    hey lubs , do you get paid there, cos you sure as heck dont seem to do much work, you a re always here
     
  4. FAST FRED
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    FAST FRED Senior Member

    The John Deere service center says this is normal and just advises to be less aggressive with throttle action.


    Deere is probably right , the electronics probably have a bit too much control authority (probably setup for a boat with smaller more rapidly responding props).

    No need to worry a few seconds of more fuel than the engine can burn cleanly will do no harm.

    I believe DEERE engines ARE Jap industrial marinizations.Not many Mfg of diesels left.


    FF
     
  5. Richard O
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    Richard O New Member

    Thanks for the feedback. The engines are Tier 2 compliant electronic engines - though not single rail.

    I don't know whether Deere manufacturers the basic engines or buys others (perhaps Japanese) and marinizes them.

    They are under warranty - they're brand new.

    But getting useful response from Deere has been nearly impossible. The Deere "authorized service dealer" has been disorganized and careless on the several commissioning issues we've had. On this, they summarily declared it normal - without taking data via laptop, etc. - and moved on. I've again asked (via a web form this time) Deere HQ to provide a live, technically competent person for me to speak with via phone. If anyone has the name and a good phone number for someone at Deere HQ that you feel could be helpful, I'd appreciate the lead.
     
  6. lazeyjack

    lazeyjack Guest

    i think fred is wrong, modern engines do not smoke, full stop, if that were the case every truck, car boat, would, puff black
    i do know that deere makes their tractors in India, I will ask my guy here, he is very strait with me
    Thats why I like Cummins, their service in next to none
     
  7. aussietrev
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    aussietrev Junior Member

    The tier2 6068 John Deere is a electronically controlled mechanical fuel pump, with not enough electronics to control much. They are not common rail, and the fuel system is only half a step ahead of a straight mechanical pumped engine. From memory, the engine does not sense boost, and so cannot adjust fuelling in acceleration mode, relying on pre-programmed fuel maps to control soot and such.
    All diesels will soot to some degree, if they dont, they arent burning diesel fuel.
    A laptop wont tell you much on this engine, except that the owners expect a laptop to fix everything , any diagnosis on these engines needs a good book.
     
  8. FAST FRED
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    FAST FRED Senior Member

    The only "smokeless" setup is found on diesel buses and trucks set up for use in California.

    THese incorperiate a throttle delay to slowly open the throttle , regardless of operator action.

    This is NOT what you want in docking a vessel.

    All tier !! will blow black on large throttle movements.

    JD doesnt visit as you have no problem.

    Use less throttle and the "problem" will not exist.

    IF the boat smokes underway at full throttle , the engines are overloaded , get smaller or less pitch props, if cruise props are not installed.

    If you have the props optimised for Long range cruse , use the tach or EGT to limit Rpm so no overloading.
     
  9. baeckmo
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    baeckmo Hydrodynamics

    Check the gear ratio for reverse; some trannies have faster running output shaft in reverse, which will require a substantial torque during manoeuvreing.
     
  10. FAST FRED
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    FAST FRED Senior Member

    Also if the shaft and prop are large say 3 or 4 inch shaft with 35+ inch prop the mass involved is qoite high , so reversing , with out stalling the engine can require a good bit of power , for long enough to see the squirt of smoke.

    The faster & more often you shift the bigger the puffs of smoke.
     
  11. aussietrev
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    aussietrev Junior Member

    Not to mention the water you are trying to move at the same time
     
  12. PAR
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    PAR Yacht Designer/Builder

    I think they might be using the VW based engine control management software, which might explain much . . .
     
  13. CDK
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    CDK retired engineer

    Lots of large truck diesels show a smoke plume when the driver steps on the throttle from idle. The fuel pump immediately responds to the new setting but the turbine takes time to supply the corresponding amount of air.
    A mechanical or electronic delay could prevent this.
     

  14. aussietrev
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    aussietrev Junior Member

    They are using in the tier 2 engines, a Stanadyne system , that hasn't been used anywhere else I have come across. The computer just takes place off the governor, but from memory, it only senses throttle, temperature, and rpm. I cant recall the last one I had apart to remember if it sensed boost, but I would expect it would, but am suspicious that it doesn't because I seem to remember it being strange in its set up for this reason. The popularity of common rail seems to have ended its promotion, but a lot of agricultural tractors use this system.
     
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