How often do you replace your impeller?

[Mo]

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.

[Mo]

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.

[Mo]

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

[ArtJ]

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.

[ArtJ]

PS I always write dates on impellers when I receive them, but have no
idea how long previously since they were manufactured.

[Dave Neptune]

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

[smosher]

I would also be in the 3 or more years crowd, but I generally put less than 30 hours per season on the A4

[Mo]

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.

[sastanley]

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.

[Mo]

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.

[JonnyQuest]

Mine's three years and about to get changed out. New impeller arrived yesterday.

[P30]

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.

[hanleyclifford]

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.

[P30]

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

[hanleyclifford]

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".