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I have a Yanmar 4JH2E. I had been under the impression that changing the raw pump impeller was just part of normal annual maintenance. I was told by a mechanic that the impeller is rated for 1,500 hours and does not need to be replaced annually. Could the 1,500 hour interval be correct or did I misunderstand him?
 

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You'd be amazed at how many 1 year old impellers are missing vanes or have cracked blade roots... For the short money, vs. an overheat, I simply swap it out yearly... There is a LOT that plays into the life of an impeller, including things like jelly fish, weeds or muscles in the intake etc.....
 

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My feeling is that it comes down to use, abuse and age. If the engine is run fairly often year-round with adequate water flow they can last a good long time. If they are run dry, hot or sit unused (installed) for a long time they break down, vanes retain a bend, crack at the base and break off. Regular inspections to confirm they're okay is important...with the pump faceplate off you can crank the engine a split second to turn the pump a little so you can check for deformed vanes.

To do a better inspection though you need to take the bloody things out to check the base of each vane for cracking, so as mainsail said, it's pretty short money to pop a new one in while you've got the pump opened up, and it gives you a little more peace of mind. I have half a dozen used ones that look fine sitting in the onboard parts box, because I can't bring myself to toss the darn things :)
 

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I change mine every year, if not more often. The pink antifreeze is not kind to impellers. Have lost 2 blades already and have disconnected the hoses and cleaned out the heat exchanger tube twice now in search of debris. I always carry a spare onboard, along with some Hondabond to seal the pump face plate.
 

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My feeling is that it comes down to use, abuse and age. If the engine is run fairly often year-round with adequate water flow they can last a good long time. If they are run dry, hot or sit unused (installed) for a long time they break down, vanes retain a bend, crack at the base and break off. Regular inspections to confirm they're okay is important...with the pump faceplate off you can crank the engine a split second to turn the pump a little so you can check for deformed vanes.

To do a better inspection though you need to take the bloody things out to check the base of each vane for cracking, so as mainsail said, it's pretty short money to pop a new one in while you've got the pump opened up, and it gives you a little more peace of mind. I have half a dozen used ones that look fine sitting in the onboard parts box, because I can't bring myself to toss the darn things :)
If the cover plate comes of my, or any customers pump, a new impeller goes in. Never had a single customer resist a new impeller when they asked me to "check" the old one... Not worth the time or the $18.00 +/- to not throw a new one in if you have the plate off...

Other thing such as winterizing and the AF chosen can also impact impeller life... It costs a customer far more for me to go chasing impeller vanes into a heat exchanger than it does to simply pop in a new impeller. Some Yanmar's are a PITA as are some Westerbeke engines but it is still not a bad job on most boats...
 

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At $20 per impeller I would be much happier at my yearly impeller change than I am now. The Yanmar 3gm30f impeller goes for more like $40. I have always thought there must be a good quality equivalent for around $20.

Does anyone know a source for a good $20 impeller available?

John
 

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11 + years as a full time liveaboard and I have never changed an impeller.

Pulled them both after 6 years prior to a transatlantic but both were fine so popped them back.

I do carry spares.
 

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Hey,

I have owned my O'day since 2006. I have changed the impeller twice and the water pump once. I inspect the impeller in the spring as part of commissioning and as long as there are no cracks in the vanes I just leave it alone.

FYI, the first time I changed the impeller I removed a perfectly good looking black impeller and installed one of the Globe 'run dry' blue impellers. Well the Globe impeller lasted less than one year before the vanes cracked at the base. After that experience I don't use Globe impellers anymore and I haven't had any problems since.

It is VERY easy to reach the impeller on my boat and I carry a spare so I can easily change one underway if I have to.

Barry
 

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Just had an discussion with a friend who changes impeller every 5 years. (about 500 hours) says never had a problem...
I change every year and will continue to do so, even though I
have to remove water pump to change.
Very bad feeling to have an impeller go and motor overheat, happened a few years ago while coming into harbor alone, between 2 large jetties, with no wind, light opposing current and large ferry bearing down fast. (Port. Jefferson, Long Island)
Oh forgot about the nasty, widespread thunderstorms expected within the hour.
Actually was a new impeller that the vanes parted from the core,
but figure odds are in my favor changing every year.
I always keep a spare aboard.
Not to leave you hanging, if any interest, on how I made out that
afternoon. Would love to tell you about my intrepid seamanship
but the truth is...
As I was attempting to turn boat away from oncoming ferry, thinking as I readied the anchor, would my anchor and short scope keep me off the jetty when the wake of the ferry past within 20-25 ft ... I looked over my shoulder, within hailing distance was a SeaTow captain coming in for the day.(First and only time I have used my membership, but worth it) Like always to be independent, but also like to use all resources available. Within a minute was under tow and was anchored before the weather came, thinking
all in all, that day I had no complaints.
Change your impeller early and often as one never knows.
 

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Hugo, I know your pain. I had an impeller go on me @ PJ as well. It was the 1st year I owned this boat. Flow and temp was always good. There was a spare left on board by the PO so I felt Ok.

Motored up the East River, had unusually good winds for the western sound that summer day, so I sailed all the way to PJ. Got to the PJ mark and go to start the engine, no flow, Temp rising fast. Try to sail into harbor, 2 kn. current against and wind right out of the channel, ferries coming and going.
Not the best place to be short tacking.

Finally got in. When I took the cover off the pump..the impeller had maybe 2 blades on it and the spare impeller I thought I had was the wrong one.

Next day... No impeller in town. No car.
Ended up finding 2 in stock , by phone 50 miles away, made the purchase with a credit card over the phone and had a taxi company bring them to me .. most expensive impeller ever.

Spent the next day fishing the old blades out of the heat exchanger, and installing the new impeller. The good news is that I got to spend time in Port Jeff and had a great time, and I got intimately acquainted with my engine's cooling system.

Since then, I change it out every year. It's cheap insurance to me. I also replaced the cover plate when I got home which over the years had a little groove worn in it.
 

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I just recently found that my manual says to replace it every 6/yrs or 1000 hours. Mine is currently 13 years and 800 hours, so I'm considering it!
 

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I still wonder why Yanmar has made it so difficult to change something that should be an annual maintenance item. On my 4jh I have to remove the water pump and alternator.

I watched some whiz at a boatyard change it by hand one time, without removing anything, but he was able to twist his hands into godawful positions...plus he was a Yanmar mechanic and did it all the time and could do it blind. I tried that a time or two and always dropped screws or the plate and realized it was easier just to remove the alternator and then the water pump.

Still cuss Yanmar for putting it where it is...on the backside of the water pump. Last one I saw at the boat show was the same way.
 

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We only put about 50 hours a year on the motor too, but change the impeller every year. As others have said, once you open it up to inspect it, you might as well replace it. This year i found a broken vane (in the heat exchanger), so I am glad we did it.

But this year I have also not been able to get the thing to stop leaking out of the cover since i replaced it last week. Motor is a Westerbeke 20B30. The gasket is just a thin paper gasket. i cleaned both surfaces and used a new gasket, but it still leaks badly.

I wonder if anyone has any tips or tricks to making the gasket seal? Or anyone know if someone makes a thicker (cork or rubber) gasket option? is it nuts to consider a little blue rtv?

Thanks
~Fortunat

Sent from my Nexus 10 using Tapatalk
 

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I have the Yanmar guy do mine aprox every year. I cant do it myself as its the 4JH3e... By the way they have changed the impeller housing to now be towards the front.

Anyway, so it take sa fully skilled YANMAR mechanic half a friggin hour to change the impeller... And a few times they have pulled ones out with blades broken.... But on careful inspection they were damaged by the screwdriver ripping them out.

Oh, and btw, Maine Sail (its not often I disagree with you) but their aint no impeller for $20! Try double that.


Mark :)
 

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I have the Yanmar guy do mine aprox every year. I cant do it myself as its the 4JH3e... By the way they have changed the impeller housing to now be towards the front.

Anyway, so it take sa fully skilled YANMAR mechanic half a friggin hour to change the impeller... And a few times they have pulled ones out with blades broken.... But on careful inspection they were damaged by the screwdriver ripping them out.

Oh, and btw, Maine Sail (its not often I disagree with you) but their aint no impeller for $20! Try double that.

Mark :)
Here's mine and it fits many other Westerbeke & Yanmar engines too.. Yanmar does not make the pump and many of them are Johnson. I can't recall the last time I installed a Yanmar "branded" impeller in a Yanmar cause I find it from the actual pump maker for significantly less...

One of the Cummins motors I work on has an impeller that is over $100.00 from Cummins. I buy the identical impeller for about $30.00 without the Cummins box..

http://www.marinepartssource.com/newdetails.asp?pnumber=JP09810B1&mfg=Johnson%20Pump&mcat1=2&mcat2=0&mcat3=0&category=&mfgcategory=Impellers&mfgno=09-810B-1
 

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That price in the link is great!!


I buy the Jabsco ones normally. I, too have never seen a Yanmar brand impeller.
But I sure need a Yanmar guy to get the damn thing in! :D

Actually, the half hour it takes the mechanic is fine because I get them to use the other half hour giving the engine a cuddle. A good pro inspection every 12 to 18 months is worth it to a mechanical dill like me :)
 

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It constantly amazes me that such a critical engine system is soooo dependent on a little rubber part that is prone to unexpected failure. I always thought that there should be a water pump alternative with all bronze / stainless parts. If there was one I'd pay several time the cost OS a standard pump.
 
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