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  • #118555

    Terry Kerr
    Participant
    Vessel Name: Olphartz
    Engines: Twin 2001 6BTAs
    Location: Florida
    Country: USA

    In my last thread “cracked exhaust” I mentioned that my exhaust cracked, filled my engine room with soot, clogging my starboard air filter and brought me off plane to limp home on the port engine.

    Key is that I was on plane.

    Replaced the exhaust and cleaned the air filters, but could not get back up on plane. Removed the air filters completely for about 60 seconds to see if that would make a difference. It did not. Max RPM achievable was about 1600 on starboard and 1800 on port. It felt like the starboard motor was holding back the port motor.

    Laser tach yesterday says my console tachometers are bang on at lower RPM and then start to vary by about 100 RPM at I reach WOT in idle. Both tachs are off almost the same.

    For instance

    Starboard Port
    VDO Laser VDO Laser
    600 = about 600 600 = about 595
    1500 = about 1550
    2200 = about 2300 2200 = about 2275
    2800= about 2900
    3050= almost exactly 3150 3040 = about 3125

    Once again I was on plane when this happened. Boat sits on a lift, so bottom is clean.

    Props have not been touched since this event (granted they were dynamically tuned just before the event and she seemed to come on plane slower, I might need to fine tune them a bit more).

    Lots of black smoke.

    Is it possible I clogged the after cooler and I am still not getting enough air under load?

    Any other possibilities?

Viewing 7 replies - 1 through 7 (of 7 total)
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  • #118919

    Terry Kerr
    Participant
    Vessel Name: Olphartz
    Engines: Twin 2001 6BTAs
    Location: Florida
    Country: USA

    Super nasty after coolers!!!!!!!!

    As advised, I removed both aftercoolers. The pic below is of the starboard engine. I forgot to get a pic of the port side, but believe it or not it made the starboard one look clean.

    The port one was full of oil down at the bottom of the air side of the housing.

    After some more research I found a video on this site that talked about the CCV and how the walker airseps sometimes fill with oil from the ccv and then the turbo sucks it up and blows it into the after cooler. I wonder if that is what happened?

    Also I discovered that there is a spot on the air filter where an indicator goes telling you when to clean/change the air filters. Both side had none. Any Idea where I get them?

    I have a buddy who works for Caterpiller, so he will take the cooler cores and steam bath them and get them cleaned up.

    The port cooler core would not come out of the housing. He is going to try to “press” it out (I’m very nervous).

    In any case, looks like I have more research to do.

    I will start a new topic on the CCVs and send pics then.

    My crank case pipe points up not down as described in the video as being a big problem. I wonder if I can keep the walker air seps and add a “puke bottle” as you guys call it?

    Also where do I find the check valve that you guys say need to be replaced regularly?

    #118696

    Terry Kerr
    Participant
    Vessel Name: Olphartz
    Engines: Twin 2001 6BTAs
    Location: Florida
    Country: USA

    Doing both motors

    Decided to go ahead and buy the “seawater side maintenance kit” for both motors and will do both at the same time.

    Looks like it comes with fat and thin o-rings. Guessing I need one or the other, but not both?

    #118689

    Terry Kerr
    Participant
    Vessel Name: Olphartz
    Engines: Twin 2001 6BTAs
    Location: Florida
    Country: USA

    scientific step by step process

    This is exactly what I needed. A one thing at a time approach. I just needed help to decide what thing first.

    I was talking to Ron Jago in Palmetto Florida (he says to say hello to Tony) and he suggested similar. He suggested to first remove the air filter and make sure the turbo actually turns (it should, it was rebuilt a few years ago), then remove the air intake hose to the aftercooler and see if it is gummed up. After that I will likely determine I need to clean the A/C anyway so previous step not really needed, but gives a preview of what to expect. After all is cleaned, then focus back on Props.

    Thanx again!!!!

    #118654

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

    Steve’s post is right on. You don’t touch props until everything else is verified 100%. Get those aftercoolers on the bench and broken down.

    #118652

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

    Terry,

    If you were able to get on plane before, then “something happened” and now you can not, then I would tend to rule out the props as the root cause of your current issue. My brain goes right to a clogged air system. When the exhaust clogged the air filter you have to imagine that the air filter allowed exhaust to pass through to other parts of the system. Like the aftercooler………

    Rev’ing in neutral puts very little load on the engine so it will not demand tons of air. when you get in gear and advance the throttles you will get a larger load more fuel and the whole system demands air. Lots of air. Restriction in the system will result in Black Smoke.

    Black Smoke is your key indicator. Lack of air in the combustion process so I would focus your efforts on cleaning the entire intake side of the system which does include the Aftercooler. If your aftercooler has not been serviced in a while and has gunk on the intake side, the exhaust could have done a real number on the air flow. Only way to know for certain is to dismount it and pull it apart. Probably a good idea anyway to get your AC serviced you may also want to take a good hard look at the intake side of the turbo. Anything that made it through the airfilter, went through the compressor side of the turbo before it got to the AC.

    So a couple of things to check. I would work 1 issue at a time as that is good scientific method.

    About the props…….
    Adding cup to a prop is like adding pitch so yes you will need to work on those again but I would want to get the black smoke and lack of revs figured out first, then go to work on the props. Also remember there is a limit to how much work can be done on any propeller so new props could be in your future.

    Case in point…….
    I just had 1 inch taken out of our props. before = 23×27 after =23×26. That reduction did nothing to my speed or fuel burn. So when I loaded all of the numbers into my spreadsheet I noticed that my prop slip was reduced but I am still 3gph total over on fuel burn at cruise. Prop Slip @2150 before = .32 Prop slip after .25 I have 1 more shot at these props before I need to get new ones. Our boat is in North West Ohio and I use an outfit that has Prop Scan. Ray scanned them before and after and sent me the scans through email. So I knew that the 23×27 stamp on the prop was accurate to start with. At winter layup we will go for 23×25 and see what that gets us. If that does not work then we are looking at new props. Mine already have Cupping so we are leaving that alone.

    Good Luck and let us know

    #118645

    Terry Kerr
    Participant
    Vessel Name: Olphartz
    Engines: Twin 2001 6BTAs
    Location: Florida
    Country: USA

    Trying to not be in denial. LOL

    Yes I have read the above several times and will likely read several more times in the future. Good stuff!

    My reason for being slightly in denial is that the boat used to get on plane with the props that I have. The props had 20x 22 stamped on them when I took them in to have then redone. I suppose it’s possible the previous owner had them adjusted to something less and I unknowingly had them put them back to 22 pitch. I also added a slight cup to them (is that a problem?). However I wonder what the pitch was before, if this actually was the case. As I mentioned before the boat planed fine before the props were redone and hit 2800 rpm (2900 corrected). After the props were done I came on plane several times but it did so a bit slower and only hit 2700 rpm on one and 2650 one the other (remember the tachs are off a bit so really 2800 and 2750). Now it won’t plane at all. Hence, the denial……

    Are you saying if the motors can hit 3150 in neutral then it should be getting enough air/fuel to reach 2900 under load if propped properly?

    It looks like I need to take them back and reduce the pitch anyway to get back to 2900. Any idea by how much? should I ask for 21.5 pitch? 21 pitch?

    If I have to spend another $600 on prop work to solve the problem, then at least I have a solution and I can get back out on the water.

    I would prefer to not take apart the aftercooler and clean if I can avoid it, but also willing if that does the trick.

    Thanx for the help!

    #118635

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

    I’m sure you’ve seen this before:

    LOW POWER / LOW RPM AND YOU HAVE DARK SMOKE:
    Propping issues: You are OVER PROPPED (overloaded or under powered in the vessel’s current configuration – call it what you like). Regardless of why, being overloaded is directly related to the propeller matching the vessels current running configuration, weight, vessel bottom condition, windage, or running gear issues/conditions, but all of these go back to the prop as they all make the engine work harder because of these conditions, and slow the vessel down overloading the engine. Also, remember the term “external to the engine” as you read further.

    AIR issues: Not getting enough air can be caused by a dirty/collapsed air cleaner, a leaking turbo hose, a filthy aftercooler or air restriction inside the aftercooler, a worn out or partially stuck turbo, or a poorly ventilated engine room. Any combo of these can restrict air to the engine causing dark smoke and further, low power.

    Maybe it’s just one of your engines (like it’s trying to carry all of the load or won’t catch up with the other one ?? It doesn’t matter, if you have dark smoke, it’s because of one or both of the above.

Viewing 7 replies - 1 through 7 (of 7 total)

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