Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines Advice test drive 6bta 250 hp 1988

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  • #77540

    Dijksman
    Participant
    Vessel Name: Lady san
    Engines: Cummins 6bta
    Location: Europe
    Country: Netherlands

    First to introduce myself i am a grand banks owner from the netherlands. I just looking for a gb with 2 Cummins 6bta with 250 hp. The engines have 4500 hrs on the hobbs. Visually inspection ok. Heatexchangers no leakages.
    Eng serialnr 44248174 for sb engine. What to watch for at a survey ? Any advice Thx Josh

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  • #78058

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

    Good to hear they hit 2,700 rpms, did you happen to photo-tach the engines to verify the tachometer readings were accurate?

    Investigate adding oil pan heaters: They will aid in cold start, reduce startup smoke, keep marine age away from your engines and keep the engine room generally warmer and drier.

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    #78046

    Dijksman
    Participant
    Vessel Name: Lady san
    Engines: Cummins 6bta
    Location: Europe
    Country: Netherlands

    Donald and Rob many thanks. As it looks now afther the sea trials both cummins running smooth idle and no probs at WOT at 2700 rpm It seams previous owner maintained the cummins well. Oil analize did not show any issues
    I did not sea a airintake grid heater on both engines. They help a lot during cold start smoke reduction in cold temerature conditions. Is it possible to reinstall this gridheaters? Any thoughts

    #77633

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

    Good simple engine that can provide many thousand more hours of service if all is setup right and operated with proper care and maintenance. I like that she’s got 4,500 hours on the clocks as that should tell you that she has been in good hands and she should be setup reasonably well.

    To my knowledge Cummins never put out a performance spec sheet on this CPL 953 engine. However, as you can see from the engine plate you took the picture of, it is rated at 2,600rpm. At seatrial, request a cold stat, meaning she sat overnight. Make the boat as heavy as reasonably heavy as possible and check WOT rpm’s and temps. The rpm’s should hit 2,700++. Any surveyor, whether it’s a typical hull guy or an engine guy, should be able to photo-tach the engines to verify the tachometer readings. Be sure this is done. No load (high idle) rpm’s should exceeded the loaded by a couple hundred rpm’s.

    The CPL 953 is a JWAC (jacket water aftercooled) engine, meaning the aftercooler has engine coolant on the water side, not sea water. This take a big unknown off the table as well as simplifies maintenance down the road should you buy the boat.

    But, this CPL 953 was equipped with underside coolant plumbing and the too small corner expansion tank. This can leave very little room for an overheat if the the coolant or seawater sides are next kept up to the highest standard.

    Take a lot of pictures of the engines and exhaust.

    That’s a start…

    FWIW, here’s the data plate from QSOL.

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    #77614

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

    Physical appearance of motor/engine room says a lot!
    Rust, grime, oil, dust indicate poor maintenance history.
    Look for a quick startup with engines cold, no excessive cranking should be necessary.
    Monitor exhaust smoke color at all times. They’ll probably smoke some when cold, but that should clear up as they warm.
    Continuous black smoke at WOT not good.
    Check maximum revs available in neutral (write is down) , should be close to same number WOT in gear.
    Good luck!

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