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View Full Version : '07 44 DB Generator Raw Water strainer prob



Jus' Chillin
08-20-2008, 02:19 PM
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:

Converse48
08-20-2008, 02:54 PM
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!

fwebster
08-20-2008, 02:57 PM
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.

Skip
08-20-2008, 03:51 PM
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

osd9
08-20-2008, 04:30 PM
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.

Robski97
08-20-2008, 09:06 PM
Sounds like u need a impellar to me ...

Rob

Four Suns
08-20-2008, 09:12 PM
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.

Jus' Chillin
08-20-2008, 09:32 PM
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.

Converse48
08-20-2008, 09:39 PM
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:.

Jus' Chillin
08-20-2008, 10:22 PM
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.

Converse48
08-20-2008, 10:28 PM
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!

Jus' Chillin
08-20-2008, 11:02 PM
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:

aquadancer
08-21-2008, 10:12 AM
Hugo - you should also check the strainer lid to make sure the gasket is fully seated and lid is on tight.

Converse48
08-21-2008, 10:17 AM
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!

Four Suns
08-21-2008, 10:18 AM
If that was the case there would be water flying all over the place since the strainer is below that water line!

Ding ding ding ding... Green balls for you...

Jus' Chillin
08-21-2008, 12:38 PM
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.

douglee25
08-21-2008, 12:53 PM
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

Skip
08-21-2008, 02:01 PM
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

Four Suns
08-21-2008, 02:09 PM
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.

douglee25
08-21-2008, 02:13 PM
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.

Four Suns
08-21-2008, 03:05 PM
The Sherwood/Hypro pumps used on the 4 cylinder Onan generators are self priming and pump about 10 gallons/minute. Given the pump is located near the water line, I don't get the priming advice.... There is a height they won't self prime but that would probably be like... 100 feet in the air? (guess) If the system is tight, then it should prime. If it doesn't, then you have a bad pump/impeller, a blockage, or are sucking in air from a hose that is above the waterline.

You may want to check out this post:

http://clubsearay.com/forum/showpost.php?p=50348&postcount=4

The blockage caused the generator to shut down when I got on plane but the generator would run fine off plane. Remember that when you are on plane, the orifice (I finally got to use that word) on the bottom of the boat has water going tangentially to it causing low pressure (suction) on the raw water circuit. Any blockage in the raw water circuit or a failing impeller can shut the generator down because the low pressure stops the water flow on a limping system. As a side note, that's why you need to have the sea cock closed on the sewage tank as the low pressure can/will suck the sewage right out of the holding tank without the discharge pump running.

So... when I see the symptom of "it'll run standing still and not on plane", I think the raw water impeller is missing a few vanes, there's crap in the heat exchanger, or there is a blockage in a hose....

My 2 cents...

Four Suns
08-21-2008, 03:20 PM
One other thing I'll throw out there is make sure you have reinforced hoses from the sea cock all the way to the suction side of the water pump on the generator. Sea Ray installed a non-reinforced hose on the suction side of the raw water pump and it took me a year to trace that down because when the hose would warm up and have any suction on it, it would collapse hence shutting off the water flow. As soon as the engine stopped, it would "re-inflate". Again... it always shut off on plane probably because more suction pressure was introduced into the system as I discussed above... I didn't find that one until I was hanging out in the engine room going down the river on plane... how fun is that...

Jus' Chillin
08-25-2008, 09:14 PM
Well boys....the truth will set you free!! Or set some bills out of your wallet free... Any way,
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.
__________________
Gary
2003 480 Sedan Bridge/QSM-11 Diesels

No insurance agents needed Gary. I just started pulling hose sections off one by one and openning the seacock at each point to check flow. Damn good thing I could always shut it!! Crazy thing is I told Festivus that I thought my impeller and pump were on the back right (or aft starboard corner..***** of a place), but actually on the Onan 9KW that I have, the hose comes out of seacock, runs across the front and toward the back right corner and enter the cabinet there; then it just passes through the cabinet wall only to run under the center of the genset back to the front side and up to a bronze little 3 bolt "housing" entering at the bottom of the housing and exiting at the top with the next hose. When I pull the hose to the inlet side of this housing and open the seacock, first thing out is practically an entire blade! That was it. I thought it odd to be in that section as I thought any "parts" would be downstream of the pump (which there still could be..). I couldn't tell, (& maybe you guys know) if that bronze kinda' skinny housing is where the impeller goes. Had to stop as I realized all the frickin' bolts are metric and all my damn tools were standard so tool shopping was fun. Anyone know if you can get the impellers any place other than an Onan dealer? Found a Onan dealer an hour away and will probably get them there in a couple of days if no other alternatives. Plus, also getting service manuals. Nobody has a breakdown of this thing or knows for sure if that's the housing huh? Anyway, I should be into it on Wednesday, and then checking downstream for parts before cranking her up.

Four Suns Blog: http://foursuns.blogspot.com (http://foursuns.blogspot.com/)

Four Suns
08-25-2008, 09:21 PM
Well... I'm glad you found it. As I said earlier, the suction created while on plane can make the water stop flowing if the impeller is bad (or a blockage). If you want to have fun, you can do a back of the envelope calculation and going 30 mph creates about 13 PSI of suction on the system so if a blade or two of the impeller are missing, you can be hosed... get it? "hosed.".. You also need to make sure you find all the pieces/blades that fell off. The heat exchanger should have one bolt on the end cap that removes it so you can clean out the parts. However, it may be behind the oil filter and so... you may be changing the oil at the same time.

The pump is a Sherwood pump... Print this out:

http://www.sherwoodpumpsdistribution.com/FileAttachments/Marine-Distribution/en-us/MPG_3022_ENGLISH.pdf

On page 12 you can match up your old impeller. Take that impeller part number and order it from... well... I can't say... go to my blog... it's listed at the bottom on my links.

Your other pumps on your mains are also Sherwood... You should also carry extra impellers for those as well.

Jus' Chillin
08-25-2008, 09:59 PM
Gary,
THANKS A MILLION !!!! I had just finished visiting your blog site and was going to tell you how cool it was that you had your "supply" sites down there for ready reference. Much appreciated Capt. I didn't think about needed an impeller removal tool or "pulley puller" basically. Don't know if my model will require it or not, but now I know what to expect. Do you change your main engines each season or 100 hrs or so? On the heat exchanger, you're right there is a bolt/cap "on each end" of this thing. Would I just remove both sides to clean it out well? Is it just a series of "channels" in there like a radiator? Thanks again man!:smt038

Four Suns
08-26-2008, 05:19 AM
I don't use an impeller puller on the generator even though I have one. I have a tool that looks like an ice pick with the tip bent over 90 degrees and that usually does the trick. Do not use a screwdriver and pry it out as you can damage the rim of the pump and the cover won't seal properly then.

You only need to clean the entrance to the heat exchanger. The exit just blows out to the muffler. Make sure you get the stuff out of the brass elbow between the water pump and the heat exchanger as that can hold a lot of impeller pieces and block water flow. Those ice pick tools come in handy for that. (You can get a 4-pack at Lowes... mine are made by Kobalt).

I change main engine impellers every season. Some people go a few years but it isn't worth the risk for me. I don't want to discover a cooling problem 3 hours from an inlet. I see you have QSC 8.3 engines so you probably have a sherwood 1700 series pump (17000 impeller). I started getting my engine impellers from these guys:

http://www.sbmar.com

They are better quality than the sherwood brand. They only make the bigger impellers though so you can't get them for your generator.

Jus' Chillin
09-10-2008, 11:59 PM
Hey Gary.
I'm not too sure about the "green balls" thing you guys mention periodically, but if it has anything to do with helpful diagnosis, hell you get a damn dozen of them!! Pulled the impeller and I literally had 1 BLADE LEFT on it!! I was going to post some pics of it for the fun of it, but the hurricane kinda kept me busy. Anywho, I used the "ice pic tool" from Sears and it was a breeze to change. Fished out about 7 blades total from the heat ex....i guess the rest blew through. The only ***** of reassembly was keeping the oring in place on the housing. The soapy water wasn't terribly effective. Suggestions for next time?? Just straight soap? Second question is re: the impellers for the big boys....since my QSC's are still under warranty, i thought i'd stay with Cummins for the impellers and those boogers were almost $200 each!! Is that what they run from the Sbmar.com site more or less?? I kept looking for something else in the box because the diff btwn the $31 for the genset impeller, and the $200 main engine impeller didn't seem to be much other than peso's. Again, Thanks A MILLION for the help!

douglee25
09-11-2008, 09:54 AM
Grease will keep the O-ring in place while you secure the housing.

Doug

Skip
09-11-2008, 12:26 PM
Hugo,
You have the same generator I do, I believe. When you reinstall your impeller it is much easier to remove the entire water pump assembly from the generator and install the impeller with the pump on a workbench (or in your lap in the ER, in my case). Trying to shoe horn the impeller in while the pump is mounted is an exercise in frustration. Pulling the water pump is a simple two hose clamp-two bolt drill.

regards
Skip

Converse48
09-11-2008, 12:32 PM
Hugo,
You have the same generator I do, I believe. When you reinstall your impeller it is much easier to remove the entire water pump assembly from the generator and install the impeller with the pump on a workbench (or in your lap in the ER, in my case). Trying to shoe horn the impeller in while the pump is mounted is an exercise in frustration. Pulling the water pump is a simple two hose clamp-two bolt drill.

regards
Skip
Skip-
I too have the same genny--- I tried your approach (removing the pump entirely), but couldn't get the damn hoses off. Is there a trick to getting the hoses loose? Fortunately, I was able to get the impeller aligned/installed on the first try. Beginners luck I guess!

And before you ask, yes, I removed the hose clamps!

Skip
09-11-2008, 12:53 PM
Tim,
Sea Ray uses a 3M adhesive, colloquially referred to as 'Gorilla Snot."
on the hoses at the factory.

It eases the installation because it acts like a lubricant up until the moment it hardens up, then you have to struggle like hell to get the hoses off again. Ever. Again.

I know this because I replaced every raw water intake hose on the mains and gen set in the grand and glorious summer of 2006 after I bought the boat. The connection on the starboard main at the Sherwood pump was especially enjoyable to remove.

I got a tube of Gorilla Snot from my local SR dealer and used it to reinstall all the new hoses.

There is no really good answer here besides brute strength and the liberal (hate that word) utilization of curse words. I don't have the boys in the ER when I am doing this sort of work. Better they learn to curse from Mom, like when I mention to her the notion of perhaps buying a 52DB with MANs next year.

I guess you could score the hose with a cutting tool-that might help get them off, but then you are doing hose and impeller replacement.


Skip

Four Suns
09-11-2008, 12:58 PM
I've never put stuff on my hoses... I like to be able to take them off for maintenance of the items they are attached to...

Jus' Chillin
09-11-2008, 03:16 PM
Thanks for the great ideas guys. I, like Gary, haven't ever put anything on other than maybe some soapy water on an inlet before replacing a hose simply to not have a major hassle in removing it for maintenance. What about the cost on the impellers for the main engines? Is that pretty much the norm ($200/impeller) or am I gettin' bent over by Cummins?? I do like using OEM while under warranty, but just curious if anybody has found anything better.

Four Suns
09-11-2008, 04:29 PM
Is that pretty much the norm ($200/impeller) or am I gettin' bent over by Cummins?? I do like using OEM while under warranty, but just curious if anybody has found anything better.

Go to http://www.sbmar.com/ and get the main impellers from them... You are getting bent over by Cummins. Cummins doesn't make impellers....

http://sbmar.com/Products/Impellers.cfm

$75 each or $130/pair for the 17000 series which I believe is what you have. Call them to verify.

Ryan
09-11-2008, 09:29 PM
Better they learn to curse from Mom, like when I mention to her the notion of perhaps buying a 52DB with MANs next year.

Come on Skip, we'll have you guys over and she will go for it, I will bring a contract to Urbana...

On topic... I had to replace my impeller in my ONAN at about 170 hours also... not a bad job, and found all the blades...

Jus' Chillin
09-13-2008, 09:31 AM
Thanks Gary! I'm sending this $800 box of rubber back Monday! They don't even send you any vaseline for $800 frickin bucks:smt013. Thanks for the help!:grin:

Jus' Chillin
09-13-2008, 09:33 AM
By the way, in the Service Manual, it calls for changing/checking the zinc bolts on heat exchanger and gear oil something or other (which must all be removed to get the water out of the system prior to changing impellers). How often do you guys change out the zinc bolts?? Where to get those bolts?? Cummins??

rondds
09-13-2008, 05:27 PM
3m adhesive on the hoses??? nice touch by SR but overkill. double clamps would do just fine.

correct me if i'm wrong, but arent all raw water pumps with rubber impellers self priming? i know your typical air condx pump utilizes a hard plastic impeller and we've all had problems with those things losing prime.

PlayDate
09-13-2008, 08:31 PM
I have been away for a few days and just got around to reading this thread. I have seen this before and I am wondering if the intake itself is clogged. The last one I saw had drawn up what looked like a tampon and the owner could not figure out why the unit was not drawing water. He burned up an impeller trying to get it to draw.

A simple check is to close the seacock, pull the top of the strainer and open the seacock. Water should overflow the top of the strainer at a rate consistent with a garden hose. If it doesn't you have found the problem.

If that is the problem, you must remove the hose from the seacock and use a half inch wooden dowel to push thru the seacock (it has to be open) and out the bottom of the boat. Yes water will come pouring in when you do this procedure but it is easily managed by the seacock.

-John

Steve36
09-13-2008, 09:46 PM
Running a generator while on the hook sometimes causes it to suck up debris such as fish. Two times this year my generator has sucked up debris. The easiest way to correct this is to take the inlet hose of the strainer (first close sea cock) and run a garden hose from the spigot in the engine room into the hose that came of the strainer.
This always clears the blockage.

Just an FYI since if the genny shuts down (reason being that it is not drawing water), its always either the impeller or a blockage.