'07 44 DB Generator Raw Water strainer prob

Discussion in 'Sport Yachts/Yachts' started by Jus' Chillin, Aug 20, 2008.

  1. Jus' Chillin

    Jus' Chillin New Member

    46
    Mar 30, 2008
    Madisonville, LA
    2007 44 Sedan Bridge
    Cummins QSC 500's
    I've cleaned my raw water strainers for my engines, and a/c several times and the genset a couple of times and wondered when any of you guys are cleaning the strainers and the housing, have you had any prob's with the generator not wanting to draw raw water again?? I have a 9kw Onan deisel genset (kubota motor) w/ about 125 hrs. After I clean the strainer on the dock, I have used a brush to loosen the grime in the housing and just stick a hose in there and flush it out. The strainer has always been pretty clean.:huh:
     
  2. Converse48

    Converse48 Active Member GOLD Sponsor

    Nov 20, 2006
    Chesapeake Bay
    See above
    See above
    To answer your question: No, I haven't had any problems getting the generator to start drawing water after cleaning the strainer. Sorry I couldn't be more helpful, but at least I answered your question!
     
  3. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    Drop the basket back in the sea strainer housing then fill with your hose and put the lid on and it should easily self-prime from there.
     
  4. Skip

    Skip New Member

    Oct 5, 2006
    Potomac River/Chesapeake Bay
    07 52 DB
    Truly Blessed III
    R6800 CRM MANs
    Thundering Towers of Teutonic Torque
    2010 Nautica 12' RIB,
    MAN R6800 CRMs
    I have an Onan 9KW in my 03 420DA and have never had a problem getting the water pump to pull water. I have perko strainers and I do not brush out the housing. I pull the strainer basket, clean it thoroughly, then place it back in the Perko, secure the lid, open the seacock, and check for leaks.

    One time I paid the impeller stupid tax by starting the generator with the seacock closed. That is in another thread.

    If you are scrubbing out the strainer body and rinsing the strainer body out with a hose, I wonder if you are introducing air into the raw water system?

    I also wonder if it is time to pull the impeller and inspect it. If you have grit and other debris in the strainer basket, some grit may be getting to the impeller and damaging the blades. On my Onan 9MDKAV, the impeller swap is easy if you first remove the water pump from the engine. This is a simple matter of a few hose clamps and two bolts-with the water pump removed the impeller swap is an easy job.
    I swap my genset impeller every 150 hours as a preventive measure, and I carry spares just in case.

    regards
    Skip
     
  5. osd9

    osd9 New Member

    Oct 3, 2006
    MidAtlantic
    2003 410DA
    Caterpillar 3126-TA w/ ZF 80-IV
    Does it eventually draw water on its own or do you need to some how re-prime before it draws water? You need to be more specific about how you can tell it does not 'want' to draw water after you clean the strainer/housing. How "did' you get it to draw water again....or didn't you? When/if you did get it to draw water, was the flow normal?

    If you are just seeing a delay from when you opened and cleaned the raw water lines, then, depending on the delay, it may be the normal time it takes for the impeller to re-prime itself.
     
    Last edited: Aug 20, 2008
  6. Robski97

    Robski97 Active Member PLATINUM Sponsor

    Jan 15, 2007
    North Bellmore, NY
    44DA
    Cummins QSC 8.3's
    Sounds like u need a impellar to me ...

    Rob
     
  7. Four Suns

    Four Suns Head Pot Stirrer TECHNICAL Contributor

    Oct 4, 2006
    Williamsburg, VA
    2003 480 DB
    Zodiac ProJet Dinghy
    Yamaha 110vx WaveRunner
    QSM-11 Diesels
    Something like that... or there is blockage or air leaking or a hose collapsing when running or something...

    I don't know why the thing would have to be primed as it's below the water line (by a good bit) and so there is positive pressure filling the thing up.
     
    Converse48 likes this.
  8. Jus' Chillin

    Jus' Chillin New Member

    46
    Mar 30, 2008
    Madisonville, LA
    2007 44 Sedan Bridge
    Cummins QSC 500's
    Hey guys. Here's what's occured. I made a trip back from Orange Beach, Alabama and the genset ran the entire 10 hr trip with no prob's and I had cleaned the strainer a few times while in Alabama, and just prior to the trip home. The next weekend, I go ahead and clean all strainers thoroughly (motors, a/c, and genset) and all of them take a little longer to self prime, but within 8-10 seconds all is in good order. The Genset would start with no problem, but by about 5 seconds after the normal time it takes to draw water and exhaust it, the Genset automatically shut down. Recap: it would start, run about 10 seconds, and auto shut down. The alarm I got on the SmartCraft for the Genset was "no raw water intake". I check the strainer a few times to make sure no blockage in the strainer. Ran the boat at full throttle, then stopped and tried to start the Genset thinking the water pressure might move any air bubbles out of the "system" --no change. Of course it is "exhausting"; simply not water and therefore shutting down. This weekend I was going to pull the hose from the strainer to the inlet on the Genset and check for "flow" to that point. It's still under warranty, but if it's a simple "maintenance" item, I didn't want to get tagged for $300 bucks for a simple fix. The only thing I did differently at "home port" vs while in Alabama, was that I cleaned the housing and not just the strainer, and in doing so, I just stick the hose in full blast and let the funk just bubble out. I'm thinking I could have forced bubbles upstream, but I thought that would clear out. Thanks for your help.
     
  9. Converse48

    Converse48 Active Member GOLD Sponsor

    Nov 20, 2006
    Chesapeake Bay
    See above
    See above
    Sounds like an impeller to me. As you noted, the genny will shut down if there is no water flow, which is a good thing (see Skip's post). And as Gary mentioned there should be no need to "prime" since the strainer is underwater. I had to (note use of phrase "had to") change my impeller at ~175 hours. Sounds like you do too. :wow:

    While you're at it, get a picture of your boat without the aft curtains... she's much purdier that way:thumbsup:.
     
    Last edited: Aug 20, 2008
  10. Jus' Chillin

    Jus' Chillin New Member

    46
    Mar 30, 2008
    Madisonville, LA
    2007 44 Sedan Bridge
    Cummins QSC 500's
    Yep, I'm afraid Skip may be right, but it's just bazarre that all of the sudden it goes from "go" to "no go". It's kind of a booger to get to the water pump on this one. Has any one changed the impeller on a similar layout to mine? I'm ordering a Service Manual for all 3 motors tomorrow. If I remove the hose to the inlet at the Genset and have good water flow there, is there any chance of an "air cavity" or whatever in the pump that I need to clear out, or is it definitely the impeller at that point?? I do need to get some spare impellers regardless.
     
  11. Converse48

    Converse48 Active Member GOLD Sponsor

    Nov 20, 2006
    Chesapeake Bay
    See above
    See above
    I'd love to help you out with you "air cavity" theory, but I'm just not seeing it. Assuming you have the same eQD-9 generator I have, the impeller is not that hard to get to. At least it is on the side of the generator that is facing you. If I recall, I had to remove a bracket and move a fuel line (not disconnect, just hold out of the way). It took me 30 minutes maybe. Order a spare while you're at it!
     
  12. Jus' Chillin

    Jus' Chillin New Member

    46
    Mar 30, 2008
    Madisonville, LA
    2007 44 Sedan Bridge
    Cummins QSC 500's
    Hey thanks anyway. Unfortunately, when you are facing the genset (which you are also facing the aft of the boat), my hose inlet into the genset is the furthest back left corner or the "starboard rear corner of the vessel". Assuming the pump is right in the same place where the hose goes in, it's gonna' suck. I couldn't figure out how any "air cavity" would be there either if you constantly have positive pressure from the raw water. Even if there was some cavity, I figure the 3rd, 4th, or 5th attempt to crank it would have sucked it through and gotten the water flowing. Thanks.:huh:
     
  13. aquadancer

    aquadancer New Member

    357
    Oct 17, 2006
    Blue Bell, PA
    2002 410DA
    CAT 3126TA
    Hugo - you should also check the strainer lid to make sure the gasket is fully seated and lid is on tight.
     
  14. Converse48

    Converse48 Active Member GOLD Sponsor

    Nov 20, 2006
    Chesapeake Bay
    See above
    See above
    If that was the case there would be water flying all over the place since the strainer is below the water line!
     
    Last edited: Aug 21, 2008
  15. Four Suns

    Four Suns Head Pot Stirrer TECHNICAL Contributor

    Oct 4, 2006
    Williamsburg, VA
    2003 480 DB
    Zodiac ProJet Dinghy
    Yamaha 110vx WaveRunner
    QSM-11 Diesels
    Ding ding ding ding... Green balls for you...
     
  16. Jus' Chillin

    Jus' Chillin New Member

    46
    Mar 30, 2008
    Madisonville, LA
    2007 44 Sedan Bridge
    Cummins QSC 500's
    Yea, someone else asked me about the lid, but that's definitely not it. It's gonna get down and dirty Saturday mornin' ! Keep you posted.
     
  17. douglee25

    douglee25 Active Member

    Jan 13, 2008
    NJ
    Cabrio
    Volvo Drivetrain
    Pull the inlet line from the strainer to the genny. Wait for water to prime out from the hose and then reconnect it to the genny.

    More than likely it's air bound.

    Doug
     
    gerryb likes this.
  18. Skip

    Skip New Member

    Oct 5, 2006
    Potomac River/Chesapeake Bay
    07 52 DB
    Truly Blessed III
    R6800 CRM MANs
    Thundering Towers of Teutonic Torque
    2010 Nautica 12' RIB,
    MAN R6800 CRMs
    if your impeller is failing, then you will need to clean the rubber chunks out of your heat exchanger. We had a thread onthat a while back-just do a quick search.

    regards
    Skip
     
  19. Four Suns

    Four Suns Head Pot Stirrer TECHNICAL Contributor

    Oct 4, 2006
    Williamsburg, VA
    2003 480 DB
    Zodiac ProJet Dinghy
    Yamaha 110vx WaveRunner
    QSM-11 Diesels
    Make sure you have your insurance agent's phone number handy in case you can't get the hose back on that is essentially below the water line.
     
  20. douglee25

    douglee25 Active Member

    Jan 13, 2008
    NJ
    Cabrio
    Volvo Drivetrain
    Yeah, make sure you have your hand by the seacock just in case!

    Doug

    Edit: I find it funny I get red balled for what is a legit answer.
     

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