Click for Lurssen Click for Horizon Click for Bering Click for Elling Click for Delta

Genset problem

Discussion in 'Technical Discussion' started by doorpro, Oct 11, 2009.

  1. doorpro

    doorpro New Member

    Joined:
    Dec 15, 2007
    Messages:
    31
    Location:
    Long Beach, Ca
    Hi Guys,

    I have just started my 16.5kw deisel generator and for the first time ever it didn't start first time, in fact it took four or five attempts.

    Usually I barely touch the starter button and she fires right up and being that I have no idea about deisel generators and dont know what to expect I was hoping that someone in here would know what to expect once i have the mechanic look at it.

    I'm sure that a service will fix all but i am still interested in knowing if this is something that I should do every year to keep her running smoothly.

    As always, best regards and thanks to all.
    Doug.
  2. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    8,040
    Location:
    Long Island, NY
    How long has it been since you last fired up? Also, Did you preheat? How's your fuel filter? How's you sea strainer? Without getting into a ton of speculation you'll probably find you cure in these answers. Good luck.
  3. doorpro

    doorpro New Member

    Joined:
    Dec 15, 2007
    Messages:
    31
    Location:
    Long Beach, Ca
    Hi,

    I start the unit up weekly and it runs for about an hour under load and as stated she would start by barely toucking the switch.

    "Pre-heat"? I throw the switch to the left and she starts. Nothing to turn on first to heat up, or am i missing something?

    The filter and sea stariner are clean and if this were a gas motor i would be looking into why the spark isnt ignighting the fuel immediately but i know that there arent any plugs so i'm wondering why the engine is turning over without ignighting.

    Honestly, I have never heard the engine turn over as she would fire so very quickly and as i said I have no clue about deisel, but i will by the end of this project...

    regards,
    Doug.
  4. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    8,040
    Location:
    Long Island, NY
    Generally the fuel is heated by use of I believe a glow plug (I'm not a mechanic). Most of the diesel gens on the boats I run require you to preheat for up to 10 seconds before starting. The ignition is usually a toggle. One direction preheat, the other ignition. However, if you've been using the gen as you say I'd tend to think it may be something a little more serious, maybe a fuel clog, but that's for your mechanic to say when he checks it hands on. Check for the preheat, then leave it to your mechanic. When he's done don't just pay the bill. Ask what it needed. You'll get educated.:D
  5. CaptPKilbride

    CaptPKilbride Senior Member

    Joined:
    Mar 16, 2004
    Messages:
    371
    Location:
    Live in Maine, work in the Gulf of Mexico
    Glowplugs heat the intake air, not the fuel. Sometimes they are located in the air intake manifold, but can be individually fitted in each cylinder head. Malfunctioning preheat system can give the symptoms the original poster described. If the original poster is not familiar with troubleshooting diesel engines, he would do well to get a mechanic onboard.
  6. CaptTom

    CaptTom Senior Member

    Joined:
    Jan 26, 2006
    Messages:
    1,883
    Location:
    Palm Beach to Ft Lauderdale
    Good advice. Although they tend to last a good long time, diesels can be tempermental and may not be as forgiving as gas engines. What make is the engine? Could be as simple as a bad shutoff solenoid (or loose or shorting wire) or no fuel flow due to pump issues or everything else previously mentioned. Did you have any issues not just starting the last time, but running and shutting down? Is the environment or raw water noticably cooler? Gloplugs can also be on another switch, typically a rocker or spring loaded that needs to be held in place so you don't forget to turn them off. Nothing worse than a burned up gloplug tip on a cold morning.
  7. Henning

    Henning Senior Member

    Joined:
    Sep 22, 2009
    Messages:
    942
    Location:
    Ft Lauderdale FL
    What year & brand genset and engine (not all diesel engines are the same) and how many total hours on it?
  8. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    8,040
    Location:
    Long Island, NY
    His statement: "if this is something that I should do every year to keep her running smoothly" leads me to question the fuel filter, but once into the fuel system it could go further than the filter . That's why I figure he's better off getting a mechanic in so he can observe and learn. CaptPKilbride, Heats the air. Makes sense. Thanks.
  9. Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    2,442
    Location:
    Miami, FL
    it's pretty hard to get specific without even knowing the brand, year and model of the darn thing!

    most gennies had a pre heat... it could be a separate swtich, it could be a different position on the key. on many diesels gennies, the glow plugs are in the cylinders themselves... if you dont' run the preheat, there will not be enough heat in the cylinders to ignite the mixture until you crank a few times and the cranking heats up the cylinders. so the symptoms you describe coudl be a preheat/glow plug problem.

    i'd start there before chasing other things. i really dont' see how the strainer can affect starting. Also if the thing runs fine under load, you can probably eliminate drity filters as well, although if you're not sure how old they are, it never hurts. don't forget the secondary filter, usually mounted on the engine.

    another possibility woudl be an air leak in the fuel system which could result in some fuel draining back and some air coming in, requiring a little more cranking. Most gennies (again we dont' know what you have) are self bleeding so a little bit of air will make it harder to start but will clear itself. on some gensets the fuel pump starts when you turn the key on, on others, when you press the run switch. try keeping it on a few seconds and see if that helps. if it does, that will indicate some air in the fuel line.

    although as the weather turns colder, it's not un usual for a diesel to take a little more cranking.

    first thing you need to do is read your owners manual to know the proper start procedure. if you dont' have it, most genset manufacturer have them on their website for download, look up the exact model and download it.
  10. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    8,040
    Location:
    Long Island, NY
    Don't think the cold is too much of a factor in Long Beach, Ca. yet. Seeing as he has "no idea about deisel generators" I think he's best off getting the mechanic before tearing apart his fuel system since he may not even know what he's looking for and the situation seems like more of a precursor than an actual problem. His gen may just want a little love and attention and his mechanic can show him how to do it before he has pieces scattered everywhere and a real problem.
  11. dennismc

    dennismc Senior Member

    Joined:
    Jan 29, 2009
    Messages:
    867
    Location:
    Vancouver BC and Florida
    I have never seen a genset start the same as a main engine, they normally have to spin over a few revolutions before they will flash up, if it did start and then run smooth under load, then I doubt a fuel problem, more likely an electronic interface issue. Just my 2c.
  12. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    6,462
    Location:
    My Office
    Hi,

    What difference is there?

    They are after all normally both Diesel Engines and some Gensets use engines that other boats use as Main Engines.
  13. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    8,040
    Location:
    Long Island, NY
    I've been on a few boats that didn't need to preheat and started like turning on a light switch. Surprised me. Defiitely the exception not the rule and I wonder if those may not be the ones with a problem.
  14. dennismc

    dennismc Senior Member

    Joined:
    Jan 29, 2009
    Messages:
    867
    Location:
    Vancouver BC and Florida
    Gen sets have to generate a minimum of 70 Volts AC current before they will start, this usually involves a few more turns of the electric plant before a full start function will take place, so the book says.....mains are not goverend with that restriction.
  15. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    6,462
    Location:
    My Office
    Hi,

    This must be a very specific stipulation that is applicable to one type of genset.

    In over 30 yrs of Marine and Diesel Engineering I have never come across this statement or requirement before.
  16. Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    2,442
    Location:
    Miami, FL
    it depends... I've heard somethign similar about either some Kohlers or some Onans requiring some voltage to keep running... personally i'm not a fan of either... i'll take a Westerbeke, Northern light or Norpro instead. much more simple circuitry.

    nycap, good point, i missed where he was from. i'm heading north tomorrow and i'm having a hard time coping with the 38 deg. forecast for Nantucket!
  17. Marmot

    Marmot Senior Member

    Joined:
    May 20, 2007
    Messages:
    3,033
    Location:
    9114 S. Central Ave
    Would like a link to that book. I too have been working on marine generators for longer than I care to admit and have never seen that one.

    On little DGs the fuel solenoid is DC, the starter is DC, the safety shutdowns are DC.If the engine cranks and the fuel solenoid is open with fuel available, the engine should start even if the generator end is in pieces on the workbench or burned out.

    What generator does this AC voltage permissive apply to? Is that 70 volts maybe a starter cutout signal? Some controllers use frequency to establish sequence controls ... I am not saying you are wrong, just very curious as this is one of the millions of things I have never heard of before.
  18. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    6,462
    Location:
    My Office
    Hi,

    That is cold for this time of year, it is colder than the upcoming daytime forecast for 15 Deg North and 80 East of there.
  19. Henning

    Henning Senior Member

    Joined:
    Sep 22, 2009
    Messages:
    942
    Location:
    Ft Lauderdale FL
    Could very well be a fuel filter issue. Many modern gensets also have an automatic heater (be it manifold or cylinder type glow plug) circuit, so I'd also be checking the connection, sticking a multi meter on the plug lead and then run a resistance check on the plug to see if I had either an open or fully closed circuit. If it does not use a heater, then it's a high compression engine, and if it'd older, it may be losing enough that it needs some cranking to warm things up a bit. There's enough possibilities that without him being a "diesel engine guy", your suggestion to bring in a pro is pretty much going to be his best solution.
  20. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    6,462
    Location:
    My Office
    Hi,

    Or the Exciter has a dud connection to the AVR or the coupling has failed in service, or the diodes have been shorted by a cable coming off and arcing on the case, or the "new generation" Electronic CAT AVR has shaken itself to bits but as its all sealed in a not easy to open box it takes a while to figure out it's a goner.

    They had not been using these for long before a service bulletin came out saying -Don't mount them where the Tray Type AVR used to be.

    In subsequent installs I always tried to salvage the Voltage,Gain and Droop Pots from the Tray Type as they did not fall apart like the cheap and nasty ones in the Electronic version and the new AVR had external terminals for connection of these pots for remote - normally switchboard mounted adjustments.

Share This Page