'07 44 DB Generator Raw Water strainer prob

Jus' Chillin

New Member
Mar 30, 2008
46
Madisonville, LA
Boat Info
2007 44 Sedan Bridge
Engines
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:
 
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!
 
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
 
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.
 
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Sounds like u need a impellar to me

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.
 
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.
 
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.
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:.
 
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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.
 
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.
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!
 
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:
 
Hugo - you should also check the strainer lid to make sure the gasket is fully seated and lid is on tight.
 
Hugo - you should also check the strainer lid to make sure the gasket is fully seated and lid is on tight.
If that was the case there would be water flying all over the place since the strainer is below the water line!
 
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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.
 
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
 
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
 
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

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.
 
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.

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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