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  • #22854

    egstasea
    Participant

    The problem was the glendening synchronizer. I don’t use the synchronizor to bring it on to plane. The port is the slave motor and the throttle cable was not engaged at the glendenning.

    The black smoke must have been the the starboard over loaded.
    I have underwater exhaust, so it is difficult to see which engine is smoking.

    #22826

    egstasea
    Participant

    I have had the boat for three boating seasons, I serviced the aftercoolers two years ago. They were serviced the Seaboard way. They came apart easily and had no corrosion. Because the boat runs so well, I was surprised how plugged up with black tar like oil they were. It cleaned up with a steam, air and wd 40. The bulk of the goo was in the mid section. The water side was clean as a whistle-again fresh water. The cores came out easy. It passed pressure tests on the first try on reassembly. I believe this is the first time they were ever serviced.
    I have it from a good source, who cruised the previous owner extensively, that they cruise primarily at trawler speeds. I concluded that this type of operation plugged the aftercoolers, and when it was been operated at normal cruise level( like I do) the turbo and charge air plumbing heated up.
    The boat also has 160 degree thermostats,which is not great for trawler speeds, but fine for cruises speeds.

    I added the egt and boost gauges last year,so I can’t tell if it made boost easier after the aftercoolers were serviced.

    The props were scanned when I bought it.

    It can’t be over loaded when it makes 2700 heavy and 2750 at normal conditions can it?

    I will photo tach it again before I lay it up for peace of mind.
    I will also repaint the turbo for a new baseline.

    #22825

    egstasea
    Participant

    6CTA intermittent rpm issue

    In cummins forum.

    #22814

    egstasea
    Participant

    Twice today I have had replies disappear. Lets try this again.

    I serviced the aftercoolers once in the three boating seasons I owned the boat – two years ago. I believe this is the first time they were serviced. I serviced they the “Seaboard way.” They came apart easy and had no corrosion. Upon reassembly they passed pressure tests on the first try. Because the boat always run so good I was surprised how plugged up the air side was. It was a black oily tar particularly in the mid section. The water side was clean as a whistle – again fresh water.
    A trusted source, who cruised with the previous owners extensively, confirmed that boat spent a high percentage of its operation at trawler speeds. The consensus at the time was that the aftercoolers caused a restriction on the air side so when it was operated at cruise speeds, including my first season, the turbo and the charge air cooler heated up. The boat has 160 degree thermostats, which are not great for trawler operation, but fine for the way I run it.

    I just added the boost and EGT gauges, so I don’t know if the engines made boost easier with clean aftercoolers.

    The props where scanned when I bought the boat, the same time I phototached the engines.

    I understand the concern about overloading, but if it is making 2750 light and 2700 loaded how can it be? I will phototach again before lay up.

    I also plan on repainting the turbos when I have them off for service, so I will have a new baseline.

    #22813

    egstasea
    Participant

    I have done the after cooler once in the three boating seasons I have owned it – two years ago. They were done the Seaboard way. They came apart easy and had no corrosion. I do not think they were ever done before I bought the boat. Cap bolts had paint on them and nothing appears to have ever been repainted. Since the boat has always run so good, I was surprised how gummed up (oily black tar) they were on the air side. Waterside was clean as a whistle – again fresh water. The consensus at the time was that since previous owner spent most of his time at trawler speed, the after coolers got plugged and restricted air flow. The boat has 160 degree thermostats which is not good for trawler type operation by the PO, but fine for the way I operate it. The trawler type operation was verified by a trustworthy person who cruised extensively with the owner. I concluded, when the boat was operated at cruise, including my first season, the turbos and charge air plumbing got hot.

    I added the boost and EGT gauges after I serviced the after coolers so I can not tell you if the boat made boost easier after the service.

    As far at the props go, they were scanned when I bought the boat. The boat has 750 hours, I have put 250 of those on it.

    When I service the turbos this winter I will repaint everything and get a new baseline.

    I know what you are driving at about overloaded. If I am making 2700 loaded and 2750 light, how can it be overloaded? I will photo tach again before lay up for piece of mind.

    #22798

    egstasea
    Participant

    Phil, The boat has always been able to make 2700 loaded to the gills. I don’t know fuel flow. I do have the original test data for this model which operates below the fuel curve. See attached pdf. My boat has 1″ less prop, makes 125 more rpm wot and is therefore even further below the fuel curve. My boat has CPL 8089, the boat was probably CPL 1929. My normal cruise rpm is 2200-2300, 22-23 knots and 900 EGT in a 1 foot chop, 1/2 fuel, full water, 2-3 people. Conditions are a little different now. See my response to Bill

    Bill, I have come around to your thinking and my original thought. I was looking at some pictures I snapped during my last run and found the port engine was running at the same RPM as starboard (on glendenning sync), but about 1 psi less boost and 50 less EGT than starboard. It seems it might have some drag on it.

    Trouble shooting is a funny thing, once you rule something out it is hard to come back to it.

    I will take both the turbos off this winter and go through them as you suggest.

    Yes the turbo is brown, Rich noticed the same thing. As I am very confident this boat is not over propped, I have not been afraid to run it. Not abuse it, but run it as it was intended.

    #22796

    egstasea
    Participant

    Brown gets lighter on the pipes, and even lighter on the incoming side of the after cooler, white on the outgoing side.

    Confirmed Tachs with photo tach when I bought it 4 years ago.

    #22794

    egstasea
    Participant

    Phil, The boat has always been able to make 2700 even load to the gills. I feel pretty confident that the boat is not over propped. I don’t have fuel flow numbers, but my speeds and rpms match Tiaras original tests very closely all across the board. See the attached test report. I realize that engine was probably an 6CTA-M2 not my-M3. That boat is just below the fuel curve. My props are 1″ less pitch. I usually run at 2200-2300 rpm and 16-18 psi boost, and get 21-23 knots in a 1 foot chop. Conditions are a bit off for the port engine now. See my response to Bill.

    Bill, I have come around to your thinking. The last trip out the engines were at the same 2250 rpm, the port engine was making 17 psi with an exhaust temp of 850, while the Starboard was making 18 psi with an exhaust temp of 900. Seems like the port turbo has a little drag on it.

    Troubleshooting is a funny thing, once you rule something out it is tough to come back around to it.

    I will take both turbos off this winter and go through them.

    Yes Bill the turbos are brown. Because I am very confident the engines are not overloaded, I have not been afraid to run to run them.

    Thanks guys – Pete

    #22771

    egstasea
    Participant

    Bill, thanks for the quick reply. A stuck turbo was my original thought too. Yesterday I did as you suggested and checked the turbo after the boat sat for 5 days. The turbo spun freely, and the boat operated perfect.

    I am happy it operated well, but I am still a little stumped at this point. I have a hard time believing that there is any corrosion on the exhaust side as I have a vey well designed exhaust, and I operate in fresh water. I guess I won’t know for sure unless I take the turbo off.

    Attached are photos of the air intake, and the exhaust for the port engine.

Viewing 9 replies - 1 through 9 (of 9 total)