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    Turbocharger test-gctid826217

    I moved the boat from Monterey to San Rafael. I brought the engines up to 2400 rpms and ran for 3 hrs. No problems. Out of no where the port engine decided to slow to 1900 rpms. The water temp was fine, the oil pressure was fine and the air intake appeared to be fine. I wasn't sure why so I slowed the starboard to 1900. About 2 hrs later the port engine slowed to 1500 rpms on it's own. All gauges showed fine. I slowed the starboard to 1500 and limped to the dock.

    My only guess is the 20 year old turbocharger. The turbocharger was not making any unusual noises bu I could not tell if it was working.

    Question - is there a way to test the turbocharger?

    If I chose replacement, is replacement simple or does the new unit require special tools, adjustments, calibration, etc.

    #2
    You can install a mechanical boost gauge to see how much boost it is producing. Also, you can remove the inlet hose and test the shaft play of the turbine to see how worn out it is.
    Matt Train
    BOC Site Team
    Chicagoland, IL

    Comment


      #3
      "scubadiver#3988" post=826217 wrote:
      I moved the boat from Monterey to San Rafael. I brought the engines up to 2400 rpms and ran for 3 hrs. No problems. Out of no where the port engine decided to slow to 1900 rpms. The water temp was fine, the oil pressure was fine and the air intake appeared to be fine. I wasn't sure why so I slowed the starboard to 1900. About 2 hrs later the port engine slowed to 1500 rpms on it's own. All gauges showed fine. I slowed the starboard to 1500 and limped to the dock.

      My only guess is the 20 year old turbocharger. The turbocharger was not making any unusual noises bu I could not tell if it was working.

      Question - is there a way to test the turbocharger?

      If I chose replacement, is replacement simple or does the new unit require special tools, adjustments, calibration, etc.
      You do not say which engines you have????

      The answer to your turbo question(s)....

      Static - You can carefully check the turbo compressor (intake side) for interference with the housing and for axial and radial play. take off the air cleaner and lightly rotate the compressor wheel looking for high spots or for 'touching' of the housing. Also lightly push it up and down(radial) and then in and out ail and look for movement if you do not have a dial indicator the in and out should be barely detectable but may have a very small 'click' feel and the up and down should be almost imperceptible. If you have a dial indicator the axial play would be best under 0.005" and the radial at 0.003" but they will run OK higher than that.

      Dynamic ÔÇô Put a low reading pressure gage on the output side of the turbo (intake manifold is typical) and bring the engine up to WOT gingerly in neutral (high idle) the boost should read in the area of 2-3 si at high idle. If you have the ability to check the boost in gear readings of 8-12 psi at 2300-2500 are typical and maybe 18-20 at WOT dependent upon rpm and loading.

      To answer the question you did not ask ÔÇô the problems you describe sound like a fuel deprivation issues with potentially blocked filters, bent hose, blocked vent or perhaps a poor lift pump.

      Hope this helps
      Northport NY

      Comment


        #4
        From the symptoms I would first replace the fuel filters.
        Jerome Robbins
        Commodore, Fidalgo Yacht Club - 2019
        Anacortes, WA

        Presently: 1999 Bayliner 2859 Ciera Express, V8-7.4L
        Previously owned:2001 Bayliner 4788 - twin 370 Cummins,
        1994 Bayliner Ciera 2855 V8-7.4L
        1994 Bayliner Classic 2252 V6-5.2L

        Comment


          #5
          If the turbo failed it would be rare to not to see a ton of black smoke. Fuel filters like above.
          1997 3788/Cummins 6BTA 5.9 M2s (Sold)
          2003 Silverton 42c/Cummins 480CEs
          2019 Cobia 240 CC
          2006 Boston Whaler 13 Sport
          1985 3270/Hino 135s (Sold)

          Vero Beach, Fl.

          Comment


            #6
            I had a similar experience on my 4588 a few years ago. I was at cruise for several hours when I "lost power". I scratched my head for a few minutes to realize I hadn't changed the fuel filters in a couple years. As such I quickly installed a new set of filters I had on board in the middle of the water. As soon as I started her back up, I knew I was in business. I regained the power and off I went to the rest of my trip without another issue. I would suggest you change/clean your fuel filters. I would bet you'll be surprised.

            Good luck,

            BJ

            OMEGA

            5788
            BJ
            OMEGA
            5788

            Comment


              #7
              Major fauxpas no my part. Lack of sleep. I had so much black smoke coming out of the port engine I thought I started an ocean forest fire. When the engine slowed to 1500 the smoke went away.

              This morning I removed the air filter and turned the turbo fan blade. It moves up and down with plenty of play. I didn't think of pulling it in/out.

              Comment


                #8
                "scubadiver#3988" post=826329 wrote:
                Major fauxpas no my part. Lack of sleep. I had so much black smoke coming out of the port engine I thought I started an ocean forest fire. When the engine slowed to 1500 the smoke went away.

                This morning I removed the air filter and turned the turbo fan blade. It moves up and down with plenty of play. I didn't think of pulling it in/out.
                Sounds like you have a culprit.

                If there is evidence of the compressor vanes hitting the housing you know for sure - or a high spot as you carefully spin it.

                If there is evidence of vanes missing and broken do nit run the engine.

                I cannot see that well in the turbo inlet so I use a digital camera to take a picture and blow it up for details.

                You still did not mention which engines you have but the first drop in rpm you experienced was likely the governor sensing the drop in boost (aneroid) and dropping fuel flow.
                Northport NY

                Comment


                  #9
                  Sorry, 1997 Cummins 315 6BTD

                  Comment


                    #10
                    Will a new turbocharger require special tools for installation, adjustments, calibration, etc.?

                    Comment


                      #11
                      No special wrenches needed I have changed one in a couple of hours. The steel gasket on the exhaust side is directional and can be reused but ordering all new gaskets is a good thing if you are doing the job. Seaboard Marine in Oxnard CA will have all the parts you need. Call them with your engine serial number.

                      He may also have a used or rebuilt one in stock.

                      https://www.sbmar.com/product-catego...hargers-parts/
                      "Adios Dinero"
                      1997 3988 with new 330 Cummins
                      Photo Credit: Whiskywizard

                      Comment


                        #12
                        Interesting parallel, we were running at 2400 across Queen Charlotte Strait when one engine slowed to about 2000 with tons of black smoke (315 Cummins). I reduced the rpm to 1500, smoke quit. All gauges seemed to be ok, so I sped back up after a couple minutes and everything was back to normal for the remainder of the summer (another 100 hrs. of running). I was guessing a fuel blockage at the pickup or in the line, that passed into the filter (I had previously gotten bad fuel and cleaned the opposite tank a year ago, when globs of congealed fuel blocked both primary 30 micron and engine filter). I did not clean this tank because I did not find any globs of crud on the filter, however there may have been a few globs of crud that got into this tank. I ran this summer using 10 micron primary filters and the vacuum gauges between the primary filters and engine always read below 2-4 pounds when I checked (I wish the gauges had a tell-tail resettable needle).

                        I was also guessing the black smoke caused by inadequate air (no turbo boost) during the event, but never suspected failed turbo that recovered and ran the remainder of the summer. Maybe I should check the turbo play just to be sure.
                        1997 4788 with Cummins 5.9 (315 hp)
                        12 ft Rendova with 40 hp Merc 4 cycle
                        Pacific NW

                        Comment


                          #13
                          Does anyone know the difference between Cummins 6 BTA & 6 BTD.

                          I have 6 BTD: not finding a turbo online.

                          I am finding turbochargers for 6 BTA everywhere.

                          Old turbo is Holset H1E.

                          Comment


                            #14
                            Sounds to me like a clogged fuel filter.

                            Comment

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