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View Poll Results: How often do you replace the impeller on your raw water pump? | |||
Once a year, or more frequently, depending on engine hours | 19 | 10.98% | |
Once every two years | 59 | 34.10% | |
Once every three years, or more | 50 | 28.90% | |
Only after it fails | 21 | 12.14% | |
I've never replaced it | 24 | 13.87% | |
Voters: 173. You may not vote on this poll |
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#26
IP: 207.210.31.104
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soaking impellers
I use two impellers..one is installed in the pump and the other is soaking in brake fluid in a small glass jar. I keep swapping them out in the beginning of each season. I think doing this should make them last indefinitely. I soaked an impeller, that was in a used pump that I bought off E-Bay, for about three months and it came back to life, even the bent fins went back to their original shape.... looked like new!! As far as the vans being too flexible? I think that the centrifugal force on the impeller itself should counter any negative effect on the pump efficiency. My understanding is that brake fluid is formulated in such a way that it helps to keep all the soft rubber parts in the braking system from drying out and cracking i.e. boots on brake cylinders and calipers, inside master cylinder.
Just my two cents worth, to each their own. Cheers Rick |
#27
IP: 151.200.252.103
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brake fluid????
Dromo, why brake fluid? That stuff is really caustic from what I understand..why not something to keep the petroleum in the impeller that isn't so bad like ATF or even motor oil? I read your comments about brake fluid, but it is still an honest question..not beating up on you..
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#28
IP: 71.168.64.77
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I wonder what the shelf life is for unused impellers before they become brittle?
I usually keep a couple of spare impellers on board and swap them out originally every year, but after speaking to Don Moyer do it every other year. This means that the stored impellers could be several years old before being used. The other thing I do is during the winter at least bi weekly, I remove the plugs squirt some mmo at the pistons and valves, turn the engine over] by hand. This also keeps impellers from becoming permanently deformed.] But again, i wonder how to gauge shelf life? Regards Art |
#29
IP: 161.213.49.1
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I don't know if it does any good but I store my spare impellers in a airtight bag. The bag also makes them easier to find. The last one I installed had been stored this way for 6 years and was still servicable.
TRUE GRIT |
#30
IP: 75.164.155.62
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Hum....,
I've only owned the boat for about two years, and a new raw water pump was installed by PO when I purchased the boat.... So I guess it's time to replace the impeller! |
#31
IP: 24.224.206.117
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Impellers
When I winterized the engine I used automotive antifreeze with the anti corrosion additives. My impeller is going on it's 4th year. This spring plan is to do my muriatic acid flush, then run the fresh water, then replace the impeller.
I did the muriatic acid flush in Sept of 2007 just before I launched the boat. That year the boat was in the water one month, then out for the winter. So I have run 2008, 2009, 2010 on the same impeller. That said, I don't know why I forgot to change it. I have remembered it many times and said "I have to change the impeller" and it was on the spring checklist last spring....There really was no excuse except I forgot to finish the list... forgot impeller and clean battery connections; everything else got done. Both worked fine all year...lucky. There were 1278 hrs on the engine when I bought the boat and now nearly 1410...hour meter shows 82 hours since 2007. My "Plan" was to take the advice of many people on here and do it every 2 years. Last edited by Mo; 04-01-2013 at 07:22 PM. |
#32
IP: 24.224.206.117
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Brake fluid shouldn't hurt the impeller though. It is specifically designed to work in high heat and not damage rubber seals in calipers and wheel cylinders...I can't see a problem with using it.
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#33
IP: 24.224.206.117
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Good point Art. I have no idea how long they should last. A manufactured date would be nice because they could be on store shelf for years before ever buying them.
That said, the spares on my boat are still fairly soft, they came with a box of spares when I bought the boat. No idea how old they are, but previous owner may have be changing every year. Best Regards Mo |
#34
IP: 71.168.64.77
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Maybe it would be a good thing for MMI to date code the ones they sell?
That way everyone would know when to use or replace them. |
#35
IP: 71.168.64.77
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PS I always write dates on impellers when I receive them, but have no
idea how long previously since they were manufactured. |
#36
IP: 96.229.195.76
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Not often enough??
I'm in the 3 or more. I usually don't touch until I notice reduced flow and a temp rise.
Dave Neptune |
#37
IP: 12.216.194.200
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I would also be in the 3 or more years crowd, but I generally put less than 30 hours per season on the A4
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#38
IP: 24.224.206.117
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I'd be thinking every 2-3 yrs.....and I have to add that to my checklist I have going....see, something else I forgot.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#39
IP: 206.125.176.5
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Back in 2010, I see JOhn Cookson commented that he stores his impellers in an airtight bag.
I do the same thing..ziploc bag, & also a scrap of rag soaked in MMO to keep it moist. Thinking back, I replaced the impeller in the pump in Jan 2009 when I rebuilt the pump...so I guess I am 3 years or more as well.. Probably time to do it again.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) Last edited by sastanley; 12-09-2012 at 06:27 PM. |
#40
IP: 24.224.152.244
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New spare as well.
Pulled mine last spring and it was still flexible so I left it in. Mine has 3 yrs on it now as well but I have a couple of spares in the box. The thing I don't usually do is keep used gear around for an emergency. Once I change out a new spare for sure.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#41
IP: 216.81.94.71
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Mine's three years and about to get changed out. New impeller arrived yesterday.
__________________
JonnyQuest Boatless right now. (Last boat, a fine 27' O'Day 1975) MS Gulf Coast |
#42
IP: 108.3.177.216
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Changed mine yesterday... then the trouble started
I became the most recent steward of a RWC '76 P30 two years ago and just changed the impeller in my Oberdorfer WP yesterday for the first time. I had noticed a water leak back there at the end of last summer although the engine still ran cold (she has no thermostat installed).
Ken talked this neophyte through what I needed to do and it actually went very well, although I did do battle with a few wasps while laying upside down in the sail locker. Impeller shaft cleaned right up and there were no leaks once reinstalled with the new impeller and the newly filled grease cup ... which I didn't know even existed The old impeller came out in 1 piece and in good shape. But for the first time ever, my engine now runs HOT. To be honest, I did not read the temp gauge but the needle did peg itself far right. She still spits water out the exhaust but not nearly as much as before. Any ideas what I may have mucked up? Or did my dickering around with it combine with the extra grease I used combine with years of sludge to partially clog the system? The acid flush sounds straightforward and is my next step. Will I do any harm just using the T fitting and existing WP to circulate the solution - as opposed to a drill pump attached to the WP outlet as some suggest? Can I ever hook the marina hose directly to my inlet T fitting or will that send water into places it is not supposed to go? The pressure flush seems a bit involved but must be worth it. Will order the kit from MMI and give it a try, though. As ever, thanks in advance for any help you can offer. Last edited by P30; 06-07-2013 at 12:10 PM. Reason: Added fact that old impeller came out in 1 piece, in good shape |
#43
IP: 107.0.6.243
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Sounds like you are the most recent victim of the "too thin impeller curse". You should take that new impeller out and carefully compare it's deck height to the old one.
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#44
IP: 108.3.177.216
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Thanks Hanley
Interesting because I did notice that the impeller blade over the cam was not compressed much. But since my only comparison is to a Volvo diesel that I sold over 20 years ago (and since my P30 ran cool enough before), I dismissed that thought. It never occurred to me that the impeller itself might be undersized. I hope to get back down there next week and will check it out ... should be a lot easier now that the wasps are all dead.
I gathered from another of your posts that you sail naked, er I mean sans thermostat. How is that working out for you? I bought her without one and she really has run well and I don't want to cross the line between preventative maintenance and "fixing something that ain't broke." By the way, might you have any advice for me on my upcoming acid flush (see previous post)? Either way, thanks again. Greg |
#45
IP: 107.0.6.243
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Naked is Good
With no thermostat and a bypass valve I can regulate operating temperature between 130 and 190 easily. Flow is where it's at. Advice on acid flush comes in the form of a question. Can you think of any thing worse than having your gizzard blasted with hot salt water everytime you go to work? How about blasting your innards with acid? Eventually you'll get thru to your "cylinders".
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#46
IP: 108.3.177.216
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Cool. A contrarian Afourian ...
... I'm lovin' it.
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#47
IP: 71.244.241.97
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This is more great and useful information guys! I just picked up my first boat (completely gutted with the disassembled A4 in boxes) last winter. I replaced the impeller as part of the engine rebuild and added an electric pump for the FWC. I had no idea of how long the impellers would last, or that you could rejuvenate the old ones.
Thank you for more great information to stick in the memory bank!
__________________
Steve Demore S/V Doin' It Right Pasadena, MD |
#48
IP: 67.186.97.244
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In Chicago I change mine [oberdofer] every 3 seasons, about 60 -75 hrs total on early model A4 I always [slowly and carefully] take the impellor and shaft out over winter layup and find this extends its' useful life. [rounded off - deburred the shaft edges so not o damage bushings] Always order a new spare and keep recent old one as emergency backup. Inspect, lightly lube and carefully reinstall in spring. Never had a impellor problem in 40+ yrs and am on only my second water pump. I have fairly decent access so job is not too difficult. A couple of times my backup has gone into someone else boat when there fins have cracked off.
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