Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › 2002 6BT Running rough ,white smoke too

  • Creator
    Topic
  • September 17, 2022 at 7:52 pm #136840

    caplyle
    Participant

    1300 hour engine, on the Great Loop for 2 months- running fine until…. We had the aft section of the 5″ exhaust hose in the eng compartment split open while running. Noticed it when I went to throttle up from a 1600 rpm cruise. Engine did not respond. Pouring out black smoke as the diesel was ingesting it’s own exhaust. Shut it down, bandaged up the hose and idled 5 miles to marina. No overheat, good oil pressure through out incident. Engine never stalled. Replaced exh hose, air filter( sooty). Next day after 2 hrs cruise I felt a ” bump” and started running a bit rough. Was also putting out moderate amount white smoke/ blue smoke, which it never has prior to this. Stopped, changed racor and on engine fuel filters. No sign of water or gunk. Good prime. Tried running with no air filter. All produced no change. Nursed it along at 1100 rpm for half the day with no change. Started to smooth out a bit later on. Brought it up to 1350 rpm- fine for 3 hours at this rpm with no smoke- than coughed and showed same symptoms near end of day.Ā In the Peoria, Il area now- looking for a tech Thoughts, ideas Ā on anything I can check are appreciated. Ā 

  • Creator
    Topic
Viewing 14 replies - 1 through 14 (of 14 total)
  • Author
    Replies
  • September 21, 2022 at 4:19 am #137043

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    “given the pictures, do you see space for a better solution here?”

    Go as high as you can with a dry riser, come down steep into a showerhead and then angle it into your exhaust going aft.Ā  A surge tube would be a nice addition.Ā  Something very much like this.

    September 20, 2022 at 7:38 pm #137038

    caplyle
    Participant

    Ok guys, heard, understood and acknowledged on the exhaust system design on this old boat. Thks to all for the honest feedback and explanations. Ā <br />Ā Tony, given the pictures, do you see space for a better solution here?

    As far as the roughness / white smoke issue- Did the smell test other day- fuel smell.Ā <br />Ran 10 hours today at 1600 rpm/ 10.2 mph. Only one stumble when I had to go to idle for a bit. Smoke was almost non existent all day. It almost seems that after I ran it full throttle at idle( to answer Tony rpm question) that things improved??

    Engine History: 2000 model 6BT installed in 2002 in a 1978 Mainship 34 Mk I. Normal maintenance items until year 2016/780 hours salt water use -rebuilt twin disc trans, new trans cooler .

    2017/ 855 hrs-Heat exchangers cleaned.

    I purchased Ā May 2022 / 1200 hrs. Ā  NEw lift pump -SBMar. Prime squeeze ball install, fresh water flush plumbing,Ā 

    In the last 2 months weve run 1800 mi- over 4000 to go on this trip Ā Approaching St Louis area- better facilities ahead for help if needed

     

    September 20, 2022 at 4:39 am #136937

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

    IMO, you need to pull the riser off the turbo forĀ  good look inside..

    One of the worst “doomed to failure” exhaust designs I have seen. Even the “blue” hose angle is iffy..Ā 

    What a Marine Diesel Turbo should look like when Inspected

     

     

     

    September 20, 2022 at 4:38 am #136936

    Steve Lewis
    Participant
    Vessel Name: Just Us
    Engines: Cummins 480CE
    Location: Marblehead, OH
    Country: USA

    Cap,

    The white “Smoke”……Ā  Have you smelled it?Ā  Is it steam or is it unburned fuel droplets?Ā  Knowing this should help point you in a direction.

    Your exhaust setup is not ideal.Ā  I believe what Donald is referring to is the fact that you have a wet elbow that holds water on shut down.Ā  It never has a chance to drain out fully on shut down.Ā  That is the Doomed to Fail article that you should have seen and read in Tony’s Tips.Ā  The proper design is to have a full dry riser that continues beyond the spill over point AND THEN you have a mixer that introduces water into the exhaust stream on the down angle.Ā  Most manufacturers get this wrong and we pay the price later.Ā  Ā 

    Without really knowing much about the rest of the history of the engine we are pretty blind.

     

    September 20, 2022 at 4:15 am #136934

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Injectors

    Have you checked here: https://www.sbmar.com/product-category/engine-components/injectors/

    September 20, 2022 at 4:12 am #136933

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Doomed to Fail

    cap, The height is good, the orientation of that mixing elbow is not.Ā  “Doomed to Fail” … search it in Tony’s Tips. https://www.sbmar.com/articles/marine-exhaust-risers-that-are-doomed-to-fail/

    September 19, 2022 at 7:23 pm #136929

    caplyle
    Participant

    Donald,

    Ā I have looked at all Tony tips. Did you see the pics I posted of the exh system?

    The elbow is as high as it can go without breaking through the cabin sole.Ā <br /><br />

    What would you do in my case?

    Thks

    September 19, 2022 at 7:17 pm #136927

    caplyle
    Participant

    Filtration : Racor 500 30mic/ FS 1000 10 mic/ on engine last chance. All were changed when prob started. No sign water or gunk. Sounded tanks today with water indicating paste- all good.Ā <br />Ā Cummins tech stopped by. Thinks 1 injector may be sticking a bit. Cummins states they dont have even one injector available for the engine- nation wide??? Told me to run a dose of Lucas injector cleaner through and see Ā if any better.

    Not easy dealing with this far from home, while in the Illinios River with no transport other than the boatĀ 

     

    I ran today between idle and 1600 for 8 hours. One stumble , Ā tomorrow another full day- we’ll see.

    September 19, 2022 at 5:23 pm #136924

    donald roth
    Participant
    Vessel Name: Paumalu
    Engines: Cummins 6BT 180 hp
    Location: where the fish are!
    Country: United States

    Go to the ā€œTonyā€™s Tipsā€ section on this website and read up on exhaust design.

    September 19, 2022 at 5:14 pm #136922

    willyok
    Participant
    Vessel Name: Aloha Lady
    Engines: Yanmar 6LY-UTE
    Location: San Diego
    Country: USA

    What kind of filtration do you have? it almost sounds and looks like you have water in your fuel.Ā 

    September 18, 2022 at 4:15 pm #136867

    caplyle
    Participant

    Full throttle in neutral 2650 smoking badly.Ā <br /><br />

    Wondering why it ran poorly for a few hours, than seemed to smooth out for the next couple hoirs than back to poor by end of day?

    Thanks

    September 18, 2022 at 3:40 pm #136866

    caplyle
    Participant

    I should also add I see a little mist coming fromcrankcase breather tube. Never noticed it before.Ā 

    September 18, 2022 at 3:38 pm #136861

    caplyle
    Participant

    Tony,Ā 

    Exhaust run is:riser, 5′ exhaust hose( split was 4′ aft of riser) , than a muffler, 2′ hose to transom.Ā <br />Cruise rpm is generally 1600. Vary between 1200 and 1800 due to traffic. Bought couple months back ,tested to 2650 for 10 min at sea all fine. Today in neutral got 2650 and ton of smoke!

    Oil and coolant levels are unchanged since problem started yesterday.

    Spun air side of turbo by hand- free and no noise/ wobble. Cracked each injector while idling- similar stumble as I did each one. Ran engine out of a can of fuel- no change.Ā <br />Pics below show smoke at idle with warm engine.Ā 

    September 18, 2022 at 11:56 am #136859

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

    What comes after the “split exhaust hose” between that and th final exit to the atmosphere?Ā  Can I see some good pics of the turbo and what is attached to it that leads to the “split hose”?Ā  Typical cruise RPM when all is right? Ever tested WOT rpm and how the engine ran at WOT?Ā  Can you check high RPM in neutral NOW? Check your oil level?Ā  Is it high?

  • Author
    Replies
Viewing 14 replies - 1 through 14 (of 14 total)

You must be logged in to reply to this topic.