Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › 370 B Won’t go above 2100

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  • May 26, 2020 at 5:54 am #98189

    James Graham
    Participant
    Vessel Name: WIDGEON
    Engines: 330 B
    Location: Cohasset, MA
    Country: USA

    32 Holland put up for winter, ran perfectly. Launched over weekend and engine won’t go over 2100. Plenty of throttle left. Went to 3000 in fall. No prop change, no nothing changed.
    No smoke, runs smooth up to 2100.
    All filters new, no air restrictions. Ran with fuel from a can, ran without air cleaner.
    Have not adjusted aneroid yet, but not sure how much to turn star wheel for adjustment.
    Thinking maybe the shaft that operates diaphram froze up over winter
    Seems to want to go but not getting fuel.
    Stuck aneroid?
    Any suggestions appreciated.
    Thanks,
    Jim

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  • June 1, 2020 at 8:16 pm #98545

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

    “No smoke to 2400”

    What happens above that ? We both know.

    100% you are flat out 3″+ over pitched———– Your engines needs to see an accurate 2925-2950 and see it easy..

    Until you are will to accept that, you are just spinning your wheels and slowly killing your engines doing it.. 25 PSI of boost at 2600 says it all..Maybe a new mechanic too.

    June 1, 2020 at 5:04 pm #98537

    Don Gardner
    Participant
    Vessel Name: OUR TIME
    Engines: Cummins 6bta 5.9 m3. 330
    Location: Blaine WA
    Country: USA

    Tony,

    I have worked through your LOW POWER TROUBLESHOOTING step by step.

    1. Tacks have been checked and are within 50 rpm of techs on dash.

    2. Ran them up to 3000 at the dock. Had more but the mechanic had me shut down at 3000.

    3. Throttle levers hit stops.

    4. No smoke from 2400 up.

    5. Aftercoolers off and serviced per your protocol in November of 2018.

    June 1, 2020 at 4:37 pm #98531

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

    Need accurate answers:

    1) Tachs have been checked for accuracy at 2400-2600 at the dock in neutral

    2) No load RPM WOT at the dock?

    3) Throttle levers on the injection pump hit the stops?

    4) Any dark or grey smoke at 2400-WOT in gear?

    5) Last time the aftercoolers were off the engines, on the bench and cores out?
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Have you really worked thru the list in this article?

    Understanding Low Power Troubleshooting

    June 1, 2020 at 8:54 am #98483

    Don Gardner
    Participant
    Vessel Name: OUR TIME
    Engines: Cummins 6bta 5.9 m3. 330
    Location: Blaine WA
    Country: USA

    Starboard serial # 45677457 Port serial # 45657204

    May 31, 2020 at 6:31 pm #98452

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

    Post good pics of your engines and engine serial numbers.

    May 28, 2020 at 7:53 pm #98389

    Don Gardner
    Participant
    Vessel Name: OUR TIME
    Engines: Cummins 6bta 5.9 m3. 330
    Location: Blaine WA
    Country: USA

    I have been following this thread because i am having a similar issue with my starboard 330. Will not go above 2000 Rpm without pushing it up by pushing but the port engine ahead of it. Can then not go over 2700 even with the port engine at full throttle. The port engine has great response. I have done everything James has done including testing the aneroid with air pressure and cleaning the line from the intake manifold. also tried adjusting the aneroid today as well as running a fuel line directly from the tank to the lift pump and return line directly to the tank. Manifold pressure is 25 psi at 2600 rpm and exhaust pressure is within acceptable range. One additional issue I have is that I can’t adjust the idle speed. Can run the adjusting screw up and down with no change.Any help will be greatly appreciated as My local Diesel Marine shop has so far put about 10 hours into this issue and have not yet found the issue.

    May 28, 2020 at 7:16 am #98331

    Oscar
    Participant
    Vessel Name: Applejack
    Engines: 6BTA 330
    Location: FL
    Country: United States

    Uups reading fast…yeah was ton of black smoke, different issue!

    May 27, 2020 at 7:54 pm #98308

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

    Good “Sherlock Holmes” find, good info, and even better that you posted what you found…..

    The aneroid saw no boost, so you got no fuel, which = no power….

    Thanks Jim……….

    May 27, 2020 at 6:16 pm #98307

    James Graham
    Participant
    Vessel Name: WIDGEON
    Engines: 330 B
    Location: Cohasset, MA
    Country: USA

    A little crud goes a long way!

    The small tube that goes from intake manifold to AFP was partially plugged as was the orifice going into the AFP. All cleaned and working fine. Just a long process of elimination and test runs. No shortage of experts hanging around due to the virus!!
    This forum is priceless.
    Thanks
    Jim

    May 27, 2020 at 5:27 pm #98306

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

    Oscar

    Stuck turbo and “No black smoke” as Jim mentioned? Remember this is a mechanical engine with a P7100 pump.

    Hard to buy into that one.

    Tony

    May 27, 2020 at 2:46 pm #98297

    Oscar
    Participant
    Vessel Name: Applejack
    Engines: 6BTA 330
    Location: FL
    Country: United States

    Happened to me once on a 330B, the turbo was stuck and would not spin up.
    I turned it with pliers and all was good for another 7-8 years I had boat. Weird but true.

    May 26, 2020 at 7:15 pm #98240

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

    Jim,

    Lazy Aneroid after sitting? Very possible.. You are totally hands-on, so, ———————–You can do 5 clicks on the wheel, OR rig up a 20 PSI air source— Rig up something and feed it some pressure.. That will tell the story right off..

    Tony.

    May 26, 2020 at 4:32 pm #98232

    Douglas Fairchild
    Participant

    Have you tried no load max RPM. Any black smoke?

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