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Lower power output from Starboard Genset

Discussion in 'Technical Discussion' started by Danvilletim, Aug 14, 2018.

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  1. Danvilletim, Aug 14, 2018
    #1
    Danvilletim

    Danvilletim Senior Member

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    we have two identical 1999 43kw generators. I believe they are Koehler w John Deere engine.

    Port runs entire boat and often shows comfortably pushing out 100ampa. The Starboard shuts off much after 75amps. And Ou course the Starboard is the quit one.

    What could be some causes of the Starboard gen set underperforming.
  2. Pascal, Aug 14, 2018
    #2
    Pascal

    Pascal Senior Member

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    How does it shuts down?

    Does it suddenly shut down because it is running hit under high load, in this case start with the basics incl strainer, impeller and clear impeller bits at the HE inlet.

    If it is a gradual shut down, with RPM dropping then it s likely a fuel issue

    Any other symptoms? Sheen on the wayer, soot, black smoke, steam...

    How many hours?
  3. Danvilletim, Aug 14, 2018
    #3
    Danvilletim

    Danvilletim Senior Member

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    I think 2500 hours but 15 years old. So lots of sitting in the past. Under 75 Amps draw it will run for days and days... But when the load gets close to 100 amps it shuts off. Captain's friend thinks it might be a diode or something.

    Id love to get it going solid because its soooooo much quiter than port which has underwater exhaust that bubbles and sends vibrations through out the boat.
  4. Pascal, Aug 14, 2018
    #4
    Pascal

    Pascal Senior Member

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    Let me ask again. How does it shut down???

    Does it run hot under a higher load? Have you looked at the temp gauge or checked temp with an ir gun when it shuts down

    Or does it start hunting, loosing RPM, and then dies down

    This is the first thing you need to know
  5. Danvilletim, Aug 14, 2018
    #5
    Danvilletim

    Danvilletim Senior Member

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    Let me ask. I seem to remember hunting and losing Rpm which I was onboard last time.
  6. Capt Ralph, Aug 14, 2018
    #6
    Capt Ralph

    Capt Ralph Senior Member

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    Nix the captains friend. It makes electricity. Diodes excite, Their job is done when it makes da juice.
    You have a weak engine. Sounds to be fuel starved. Filters, Lines, Pump, and more line issues come to mind.
    Underwater exhaust on a gen-set??? Somebody closed off the gas sep, above water thru hull.
  7. Pascal, Aug 15, 2018
    #7
    Pascal

    Pascal Senior Member

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    If that s the case, start with filters (prim and sec)
  8. Capt J, Aug 15, 2018
    #8
    Capt J

    Capt J Senior Member

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    That, it's also possible the generator needs a tune up......valves adjusted, rack adjusted, etc. But it sounds to me like a loss of power that cannot carry a larger load.
  9. Danvilletim, Aug 15, 2018
    #9
    Danvilletim

    Danvilletim Senior Member

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    Good advice.. Filters were changed a week ago. Could injectors be a culprit. What all would you ask for in a tune up?
  10. Capt Ralph, Aug 15, 2018
    #10
    Capt Ralph

    Capt Ralph Senior Member

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    Later Deere gen-sets are computer driven. A JD tech is required to read and check the injectors. If one is replaced or serviced, the computer needs to be updated with the new specs.
    20 year old & older Deere gen set engines were base on Yanmar blocks. A good tech can work on them without a lap top computer.

    Computer or mechanical, IMO you have a fuel starved engine or to much hardened slobber in the exhaust manifold.

    43KW gen sets are in a world that really need a load to keep the exhaust hot and clear. Under-loaded motors will fill that exhaust manifold up with a hard crust in a few hours.
    Restricted exhaust will shut a small motor down when it TRIES to preform. Even if it's turbo driven.
    Had this problem on a fine Kohler turbo gen set.
  11. Capt J, Aug 15, 2018
    #11
    Capt J

    Capt J Senior Member

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    Could be injectors, could be fuel pump, injector pump, dead cylinder, governor, and on and on. A tune up usually adjusts valves, adjusts governor etc. You need a competent mechanic out to diagnose what's going on with it. Could even be a marginal fuel system and shutting down on overheat when more of a demand is placed on the unit, you just don't know.
  12. Pascal, Aug 15, 2018
    #12
    Pascal

    Pascal Senior Member

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    Well if it s hunting and loosing rpm it s not an overhead issue.

    You need a mechanic familiar with out these units unless you want to pay for the guys on the job training

    Earlier this year I had a small leak on one of our Ohno 27.5 injection pump. I asked my cat mechanic and he said they could replace the pump. Well... after 4 hours of trying to get the new pump working he was smart enough to admit it was time to call a guy who was really familiar with these units.... He had it running in 15 minutes.