Hi all,
As some of you may have seen on another thread, I replaced the impeller on my Sherwood pump before splash, and immediately after splash experienced severe (4 drops/second) leakage from the weep holes. I replaced it with a brand new Sherwood G908 from Westerbeke (yes, I know that's a bad idea, but I had reasons that were specific to me). The new pump is generally better, weeping only about 1 drop per minute. However, my expectation was that zero drops should be seen on a brand new pump (unless there's some break-in period that I'm not aware of). I'll call the Westerbeke distributor Tuesday to inquire about whether I have a defective pump.
While there is absolutely no reason to believe that this leakage is caused by backpressure from a blockage or other problem in my heat exchanger or exhaust system, I do need to consider this possibility (especially since I expect that the Wb distributor will try to pin the blame on something else). I see lots of stuff on the Tech Wiki about replacing the exhaust riser, but not much about diagnosing the existing system to see if I actually have a problem there. Do any of you have any tricks to diagnose this without having to dismantle my exhaust riser, etc? Please post here or provide a link to existing posts/articles on the topic. Next time I'm at the boat I'll also remove the HX end plate to inspect, though last time I did this everything looked fine and I've never lost any impeller blades or anything else since then.
Quote from: Breakin Away on May 27, 2018, 07:41:04 PM
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>>>>>>>>>>>>>>>The new pump is generally better, weeping only about 1 drop per minute. However, my expectation was that zero drops should be seen on a brand new pump (unless there's some break-in period that I'm not aware of). I'll call the Westerbeke distributor Tuesday to inquire about whether I have a defective pump.
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I've just completed a rebuild of our rw pump, second time. Weeping should be ZERO. Period. NONE. Nada, zip, zilch.
The seals are where it could leak. Indeed, the ONLY place.
I do not understand any possible connection between the riser and the rw pump. The riser is air, until the nipple. If you need to know, take the hose off the nipple and look inside.
I think you're over-complicating a simple defect: your new rw pump is leaking.
Ahh, well, whaddya expect, it's a Sherwood. :D:D:D
Care to explain "Generally better?" Really?
Quote from: Stu Jackson on May 27, 2018, 08:30:42 PM
....I do not understand any possible connection between the riser and the rw pump. The riser is air, until the nipple. If you need to know, take the hose off the nipple and look inside.
I think you're over-complicating a simple defect: your new rw pump is leaking...
No seal can withstand infinite pressure. So if there's a blockage building up in the HX or in the injection elbow, it could cause leaking through the seal.
Quote from: Stu Jackson on May 27, 2018, 08:30:42 PM
Care to explain "Generally better?" Really?
One drop/minute is generally better than four drops a second. Roughly speaking, it's 360x better.
I hear you. I do not recall your earlier experience, so perhaps a link to that discussion would be helpful, and we could see for ourselves the "improvement." :D I usually can keep track of them, but I've had my own "boat issues" these last few weeks...
You're right, it shouldn't be leaking at all.
If I understand your drift, you're indirectly asking if the vendor could wiggle out of responsibility. Then it would appear that any backpressure would have to be pretty hefty to blow a seal. If water is coming out of your exhaust hose through the muffler, and your intake strainer is clear, wouldn't that preclude and claims for pressure related issues?
R,
I had previously emailed you a procedure;
1) Ck for Blockage in the heat exchanger tubes. Pull the caps and make sure the tubes are clear (coat hanger).
2) pull the hose on the injection wye, make sure there is no blockage (feel down into the wye with a coat hanger or something like a short dowel with a larger diameter.
***********
You could also pull the RWP to Hx hose and apply dock water (throttle down the flow/pressure), while you leave the muffler drain open. Only a SMALL amt of water, you don't want to flood the muffler/riser. Or use air pressure to check for free passage.
In 30 yrs pf pumps, I have not seen a bad Sw pump out of the gate. By "bad", I don't mean "crap" (it is) I mean "defective."
I believe but have no numbers to back it up, that either pump won't develop enough pressure to blow a seal.
-k
Oh also. Did you get a pic of your PO setup? What size is the inlet elbow/hose?
-k
Thanks, Ken. Sorry, I had forgotten that your prior emails had mentioned this.
You were correct all along, my inlet barb is 5/8", per the factory setup. When I changed my impeller 2 months ago (on the hard), I pulled only one hose off to be able to maneuver the pump into position to remove the (stuck) impeller. I thought it was the inlet one, but it was actually the outlet. I had a vivid memory of seeing (and measuring) the 7/8" barb, but it was the outlet barb that I had seen, not the inlet.
Quote from: KWKloeber on May 28, 2018, 09:41:10 AM
...In 30 yrs pf pumps, I have not seen a bad Sw pump out of the gate. By "bad", I don't mean "crap" (it is) I mean "defective."
I believe but have no numbers to back it up, that either pump won't develop enough pressure to blow a seal.
Yes, this does appear to be an odd case. If the pump doesn't develop enough pressure to blow a seal (which makes sense, since I would expect the impeller fins would just start to bend and leak) and you haven't seen a defective pump before, then one way or another we're looking at a new first.
One other comment, which I'm sure is going to get you saying "I told you so," I was very unimpressed with the condition of the pump housing. It was in a fully unopened box with blue plastic protectors in the threads and over the flange, but the flange end had some significant dings in it. It shocked me enough that I snapped a picture. I don't think these dings would affect performance, but it still gives a very poor impression of quality. In the two pics below, you'll see the new pump with dings, and then my old pump with pristine flange section. [EDIT: These dings actually give the impression that this pump might have been (abused and) returned before, and then re-packed in a fresh box by Westerbeke. Not sure, but something must have caused those dings in the flange.]
Obviously my original intent to have in immediate drop-on replacement is not going to work out. I did get to do some sailing this weekend, but now the boat appears likely to have to go out of service while I work out this issue. It's frustrating, but I've also got a flaky depth sounder that I need to fix, so that would have been taking away from some sailing time anyway.
Did it come from a reputable Wb dealer? A Wb distributor? Depco?
That doesn't look pristine, wonder if it's a return?
A small drip like that won't affect performance or your sailing while you have some time off.
-k
<<When I changed my impeller 2 months ago (on the hard), I pulled only one hose off>>
Ahhhh. (I'm not beating you up, just making a point to everyone about 'complete info".)
With that info in hand I could have guaranteed you had the OEM sizes. You can't repkace the impeller by removing only the inlet hose, so I'd know you defo measured the 7/8" outlet barb.
Even what may seem like an insignificant detail can help sleuth a problem. :D 😳
Quote from: KWKloeber on May 28, 2018, 11:32:45 AM
<<When I changed my impeller 2 months ago (on the hard), I pulled only one hose off>>
Ahhhh. (I'm not beating you up, just making a point to everyone about 'complete info".)
With that info in hand I could have guaranteed you had the OEM sizes. You can't repkace the impeller by removing only the inlet hose, so I'd know you defo measured the 7/8" outlet barb.
Even what may seem like an insignificant detail can help sleuth a problem. :D 😳
All that's correct, and you were right all the time. I didn't know what "complete info" I needed until after I left the boat (in Maryland) and flew to Milwaukee for the week. It's the cost of having a long-distance job. Even when I'm at home, I'm still 2 hours away from the boat, so long-distance diagnoses are really difficult. And every time I'm driving home from the boat I get a flood of ideas on what else I should have done to diagnose xyz problem.
Quote from: KWKloeber on May 28, 2018, 11:24:42 AM
Did it come from a reputable Wb dealer? A Wb distributor? Depco?
That doesn't look pristine, wonder if it's a return?...
Hard to believe that it came out of the factory that way, but the box showed no signs of having ever been open.
I bought it from Hansen Marine, who is the authorized distributor for eastern Pennsylvania, where I live. I'll be on the phone with him tomorrow. If I've lost the opportunity for a quick turnaround swap-out, I'd actually prefer to rebuild my old pump. I'm going to search the Tech sections right now for Ron Hill's Sherwood rebuild instructions. I'll try to take apart the old pump today if I have the right tools here. Maybe I can get the needed parts in quick enough to ask Hansen to take the pump back and keep it (if the shaft is in OK shape).
Hansen is reputable. It's hard to believe it came from Sherwood that way.
If Wb manufactured it, then i wouldn't doubt it. I've posted before that I had to return nearly $1000 in parts, multiple units that were mis manufactured and Wb didn't catch it and shipped them out. Double threaded risers, ports with threads not cut to full depth, exh flanges with threads on only half the ID circumference. All offshore no doubt.
What I've seen that is manufactured in house is ok.
Ken
Sent from my phone
FWIW, I'm starting to take my old pump apart. Both the gasket and O-ring are perfectly seated, eliminating the possibility that they were the source of the leak. Looks like it definitely came out of the weep hole. (Couldn't trace the rust stain, because the leak was so fast that water rusted the entire iron body.) Impeller looks great also, since that was replaced just before all this weeping stuff started.
Interestingly, my copper C-clip is not rusted at all. In fact, it's in really good shape. Of course, Murphy's law guaranteed that my snap-ring tool (which I've only used once) is at the boat (2 hours away). So it's off to the store to buy another one (that I will probably only use once).
If there is scoring on the shaft, where would I see it? Ron's tech article sounds like I may only need a couple of water-side bearings and a stainless steel C-clip replacement. So I don't need a total rebuild kit (especially with the new impeller already in there)? Are there other recommended parts?
I'm not familiar with rebuilding a Sw, 'er Wb pump, but I'd imagine scoring would be at the seal, where it tends to show up in in Ob. A worn bearing or shaft at that location would tend to wear/elongate the seal.
Since you're "down" why not just replace w/ the Ob and "be done with it"?
-k
Breaking : To check if there is a blockage in the exhaust water system (from the raw water pump to the HX to the riser to the muffler)
Just take off the hose from the RW pump and blow into it. It should be free!!
A thought
Breaking : If I bought a new pump (any brand) and I installed it and it leaked!!
Guess What !! I'd call who ever and ship it back to them and get a replacement that didn't leak!!
A thought
Quote from: Ron Hill on May 28, 2018, 02:27:39 PM
Breaking : To check if there is a blockage in the exhaust water system (from the raw water pump to the HX to the riser to the muffler)
Just take off the hose from the RW pump and blow into it. It should be free!!
A thought
I wanted to do that, but the hose did not extend out far enough from the motor for me to get to it, and I didn't have the needed adapters to extend it. I'll try to take together the needed parts to do that next time I go to the boat. I also borrowed a radiator tester from Autozone to do the same thing, but was chased off the boat yesterday by big thunderstorms that came through. Couldn't wait them out because I ran out of time.
Quote from: Ron Hill on May 28, 2018, 02:32:02 PM
Breaking : If I bought a new pump (any brand) and I installed it and it leaked!!
Guess What !! I'd call who ever and ship it back to them and get a replacement that didn't leak!!
A thought
I might go one further and just ask for my money back. Not sure he'll do that, but I'll make the argument that since his pump didn't fix it immediately, I used the non-sailing time to disassemble my current pump and am prepared to do a quick rebuild.
I used your instructions to take the water side parts off. When I removed the copper C-clip, it was in great shape. However, the stuff underneath did not spring up at all. I removed all the other components, and the ceramic discs are in great shape. Disc faces are very smooth and shiny - not scored at all. The rubber bushings look good too, after cleaning. The spring and its rubber bushing were dirty, but easily cleaned. The shaft is not scored. Now when I put it all back in, the "springiness" is back.
My guess is that some grime got in under the rubber bushing (under the white ceramic disc) and prevented the spring from being able to push the discs together sufficiently. So more water got in, and then mucked up the spring.
I'm tempted to just put it all back together and see what happens. But at the same time, I might get some rebuild parts for just the water side (based on Ron's suggestion). I may have to get those parts from Hansen since they already have my money - we'll see. Otherwise, I'll be looking for other sources, including you, Ken, if you have them and are willing to sell them.
One question for Ron: Your test says that you didn't rebuild the oil side because it seldom leaks. But your pictures sure look like you bent up the oil side seal and forcibly removed it. Can you explain the discrepancy? [EDIT: I now realize that the part that was bent up and forcibly removed is the bottom of the spring assembly.]
Other suggestions?
A radiator tester is meant to test that the system is holding pressure, not to gauge how much flow is going thru the circuit. If you have as much as a pinhole Through a blockage in the injection wye, it will let air readily through it and you won't really be able to detect the blockage using a radiator tester because it won't hold pressure.
What you want is to push a large flow (water, air, breath) for a short period. Not hold a vacuum for a long period.
How would you attach a radiator tester to the RWP circuit?
If you're getting good flow from your RWP, out the transom, then you don't have a (significant) blockage at the wye.
Likewise, if you're not overheating then you're getting decent flow through the HX which means flow through the injection wye, which means you don't have a blockage.
On the B-series, it's a harder to troubleshoot the RWP than it is on the M-25/XP/XPA/XPA(C), M-35/A (et al). There's a just not good access to the hose on the business end.
If you pinch the RWP to Hx hose closed, or remove at the Hx and plug it, does the REP weep more? ie, blow past the seal?
If you send yours to Depco they could refurb it overnight (if I asked them nicely.) Another thought.
Or throw an Ob on in less time than you're effin around with yours! Rebuild it later to hold for a spare.
Quote from: KWKloeber on May 28, 2018, 04:23:45 PM
A radiator tester is meant to test that the system is holding pressure, not to gauge how much flow is going thru the circuit. If you have as much as a pinhole Through a blockage in the injection wye, it will let air readily through it and you won't really be able to detect the blockage using a radiator tester because it won't hold pressure.
What you want is to push a large flow (water, air, breath) for a short period. Not hold a vacuum for a long period.
How would you attach a radiator tester to the RWP circuit?
If you're getting good flow from your RWP, out the transom, then you don't have a (significant) blockage at the wye.
Likewise, if you're not overheating then you're getting decent flow through the HX which means flow through the injection wye, which means you don't have a blockage.
On the B-series, it's a harder to troubleshoot the RWP than it is on the M-25/XP/XPA/XPA(C), M-35/A (et al). There's a just not good access to the hose on the business end.
If you pinch the RWP to Hx hose closed, or remove at the Hx and plug it, does the REP weep more? ie, blow past the seal?
If you send yours to Depco they could refurb it overnight (if I asked them nicely.) Another thought.
Or throw an Ob on in less time than you're effin around with yours! Rebuild it later to hold for a spare.
All valid points and good ideas.
My thinking with the radiator tester is that I could fill the outlet hose with water, jam the radiator tester on the end, pressure it up a little, and get a sense for how fast the
water was exiting by how fast the pressure drops. (Clearly air would go through a pinhole, but water's viscosity would make it much slower.) I think someone here mentioned doing that with his system. The tester that I borrowed from AutoZone has a couple of conical shaped rubber fittings that expand when twisted, so I could jam them into the hose end and twist to make a seal. I knew it was a long shot, but it cost me nothing, and with the boat 2 hours away I wanted to err on the side of having something extra. Ultimately I didn't get to try it yesterday because I was chased away by a pretty severe lightning storm.
The radiator tester is the same one I borrow every spring to test the freshwater side of my cooling system.
I like Ron's suggestion to just blow through the outlet hose. I'll pull together the necessary fittings to extend the hose out to where I can reach it.
As I've mentioned before, there is absolutely no sign of any blockage anywhere. Everything is working great, except for two leaky water pumps. Temperature always holds steady at 165, and there's plenty of water coming out the exhaust. No noticeable decrease from when I bought the boat two years ago.
Regarding pinching the hoses, are the inlet and/or outlet wire reinforced? I'm interested for a couple reasons, including a plan to cut the inlet and install garden hose fittings for easy belt replacement (and an easy way to winterize).
Rebuilding the Sherwood is super easy (and halfway done already), so that's my first option if I can get parts fast enough and/or re-use the current ones after cleaning them up. If I need a whole new pump the Ob will be a strong candidate.
Question for Ron: When I referred to "forcibly removed" in my prior post, I was referring to these pictures, especially the sheet metal part with the pried up edges that you removed:
(http://c34.org/bbs/index.php?action=dlattach;topic=7489.0;attach=3962;image)
(http://c34.org/bbs/index.php?action=dlattach;topic=7489.0;attach=3961;image)
Compare those pics to my pump housing. This begs the question, have I removed everything I need to remove yet? Or do I need to pry up the edges of the sheet metal piece in the bottom and pry it out like you did? It seems to be in perfectly fine condition, so I'd be tempted to leave it unless there's something that I'm not seeing. And I'm assuming that this metal piece is the part to which the spring assembly is attached using Permatex. Is that right?
[EDIT: To partaially answer my own question, after re-reading Ron's instructions, it looks like the part I'm asking about is the "bottom of the old spring assembly" which I need to "take the end of a flat tip screwdriver and pry up the edges". I guess my revised question is if I choose to leave this piece in place (since everything looks to be in such pristine shape after cleaning up), what do I use to "re-glue" the spring assembly back into this metal bottom?]
Gotcha on the tester, I didn't know they had those kind of expand-a-plugs.
The outlet is installed by Universal and is **supposed** to be reinforced. THe seawatere us installed by CTY, and must be reinforced, but who knows.......?
I don't know that I'd use GHT fittings on the water line side of the pump but YBYC. Lanacote or SuperLube ptfe gel on the barbs and the hose will come off like butter. I think I mentioned before that those elbows are cast brass not bronze and not recommended for salt water. Just a public service announcement. 🤓
Breaking : You are really testing my memory from 7/8? years ago.
The reason I mentioned the screwdriver tip as I recall that piece is pressed in place. No glue!!
As I recall I pried up the edges and clamped on with a vice grips and worked it out. To reseat the new one I recall using a piece of 1" PVC pipe with some Vaseline on the edges and tapped it in place.
Hope this helps
A thought