• Creator
    Topic
  • #25269

    captscottc
    Participant
    Vessel Name: Island Girl
    Engines: 6 BTA 5.9's
    Location: Southeast Louisiana
    Country: United States

    Ok, before I order a couple of new air filters for my 6 BTA 5.9’s I have in my cart, I would very much appreciate any info on whether if there may be another related issue to my engines (black) smoking a bit- at all speeds including idle. Leaving a lot of dreaded nasty soot stains on the stern. Other than that, the boat runs like a beast. The boat is a sea ray 370 sedan bridge and the engines have only 1700 hrs on complete overhauls. I recently purchased the boat (in July this year) and engines were serviced March of this year. I do not know if the air filters were included in the servicing but am “assuming” not, hence the “black stacking”. All input is appreciated. It’s my first gig with cummins, seems in the past I always got the ones with screaming Detroits, lol. Thanks in advance people. Peace

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  • #25288

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    Now we are down to this if you want to sort this out.

    1) I want a full picture of the boat the engines are installed in

    2) I want engine serial numbers

    3) I want to know your wide oped throttle RPM wne the vessel is fully loaded

    4) I want to SEE the engines as installed in the vessel

    5) At what RPM do you CRUISE at and what is the vessel speed at that RPM

    5 very easy questions that need specific answers/pictures..

    Then, I will be in a much better position to understand the issue..

    Tony

    #25285

    captscottc
    Participant
    Vessel Name: Island Girl
    Engines: 6 BTA 5.9's
    Location: Southeast Louisiana
    Country: United States

    Everyone thanks

    I guess I misprinted on the engine hours info. They weren’t rebuilt at 1700 hrs, but rather have only 1700 hrs at present. Smoke at idle is extremely minimal but there just the same and nothing nice as you know when the wind is against you. The black stacking at cruise isn’t bellowing like a locomotive on Bonanza, but again, there just the same. When I look aft while running, a faint translucent brown/black exhaust cloud follows. In my tugboat world, we refer to it as “black stacking” whether heavy or light. 99% resulting in air filters need changing or “silencers and screens” need cleaning if so equipped (on our 12/71 Detroit’s). Cummins, though I’m unfortunately not so familiar with, was assuming the same though I know it’s apples and oranges so to speak. 2 stroke vs 4 stroke, turbos and charged air coolers vs intake blowers etc etc.
    The prop set up is upgraded to the 4 blade and I have the paperwork on board as to the engineering company that did the prop size /ratio set up. Seems to perform extremely well even at very slow maneuvering.
    I hate the thought of starting to pull anything apart to inspect but am thinking maybe starting with inspecting the turbos for nicks, bent blades or soot build up then going from there? Just seems so much easier to pop on two new filters and see what I get, lol. Thanks big time guys. I attached a photo of one of the other boats I get to drive…:)

    #25274

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    Cap Scottc,

    Do you know why the engine required a “complete rebuild” at 1700 hours? You need to be sure that what lead to that, is sill not happening..

    Anytime an engine like this requires a rebuild at such low hours only means 1 of 2 things–A very poor installation and and overall set-up, and /or a total lack of maintenance that usually comes down the the “Nut behind the Wheel”..

    I’d look into it..

    Tony

    #25271

    Bill Desmarais
    Moderator
    Vessel Name: Extremist
    Engines: Cummins 6BTA 370
    Location: Portsmouth, NH
    Country: United States

    Scott,

    You’ll find that “low power” black smoke has a few more variable causes other than dirty air intake filters.

    If you haven’t already, begin reading the articles in “Tony’s Tips”

    Here’s one.

    Understanding Low Power Troubleshooting

    Keep us posted with a bit more info going forward.

    Have you photo tached the engine rpms to assess “over propping” ??

    Regards, Bill D

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