Beware: non-Yanmar impellers for 4JH series may not prime

[bbalan]

Hi All,
I replaced the impeller (part #129470-42532) on my 4JH2-TE with an aftermarket brand. There are many advertised out there from various sellers that say they are a direct replacement. However, most (if not all) of the aftermarket impellers have 12 vanes and not 9 like the original part. Even Globe says their 075 12-vane is a replacement for the above part number.


Long story short, whenever we sailed on a blue water voyage, the pump would not prime at the end of the voyage. No water in the exhaust. Starting up at anchor was no problem. Sailing in smooth water, no problem. It was only in rougher conditions. After replacing hoses, examining the entire cooling system, reversing the raw water pump cover plate, etc. etc., we realized it was the change of the impeller. Put in a Yanmar impeller and all is good.


So stick with Yanmar on your impeller for this series of engine.
Cheers,
Bruce
Hiva Oa, FP

[Fuss]

i had that too but with a different engine. Always use the original, except in emergencies.

[derfy]

Yep, I learned this one the hard way. Use Yanmar. I also change the impeller every 300 h instead of the prescribed 600 h on my 4JHE. Also change them at least once each calendar year. I have been told Johnson impellers are okay, but cannot attest to it. Lube the new blades with glycerin - it dissolves and will not clog the heat exchanger.

Were any impeller blades broken off? If so, the rubber bits are now clogging the tubes in your heat exchanger. You may have to pull the exchanger and have it cleared (and cleaned while you are at it). Watch your temperature closely.

I now carry all the heat exchanger o-rings and gaskets so it can be pulled in the boondocks if need be.

[pcmm]

Originally Posted by bbalan

Hi All,
I replaced the impeller (part #129470-42532) on my 4JH2-TE with an aftermarket brand. There are many advertised out there from various sellers that say they are a direct replacement. However, most (if not all) of the aftermarket impellers have 12 vanes and not 9 like the original part. Even Globe says their 075 12-vane is a replacement for the above part number.


Long story short, whenever we sailed on a blue water voyage, the pump would not prime at the end of the voyage. No water in the exhaust. Starting up at anchor was no problem. Sailing in smooth water, no problem. It was only in rougher conditions. After replacing hoses, examining the entire cooling system, reversing the raw water pump cover plate, etc. etc., we realized it was the change of the impeller. Put in a Yanmar impeller and all is good.


So stick with Yanmar on your impeller for this series of engine.
Cheers,
Bruce
Hiva Oa, FP

I've Had sinilar experience. Its temping to use a non OEM impeller, specially since the cost savings is significant! Its tough droping $120 for a single impeller, vs $35 for an other brand. But the performance difference is significant!

[sailorboy1]

To me it is worth getting the Yanmar im peller just because it is threaded for the puller

[hlev00]

I began having the same symptom this past season - losing prime when sailing in rough'ish conditions; no problem when at anchor or calm sailing conditions. I've replace cover plate, wear plate, and used Yanmar impellers. Unfortunately that didn't fix my problem. I am going through the raw water system this off season and likely replacing the raw water pump. It is great to hear you found a solution to your problem. I wish it was a universal fix to the symptoms.

[pcmm]

Originally Posted by sailorboy1

To me it is worth getting the Yanmar im peller just because it is threaded for the puller

I wish they still had the thread! the one with the thread ha been "superceded" by one that doesn't have a thread any longer! but I've got a way around that problem now. Hose pipe pliers. reach in and grab the impeller. Actually easier than the OEM puller!

[HopCar]

I wonder if the problem is specific to Globe Impellers? Many years ago when Globe first started selling their blue impellers, their run dry claims sounded really good so I started selling them. The first few I sold came back with broken blades very quickly. I stopped selling them. I’m surprised they’re still in business. Maybe they fixed the broken blade problem.

[sv_pelagia]

I recently purchased Yanmar impellers with the NEW part number (they were not old stock) and YES they have the threaded part.

[hlev00]

Originally Posted by sv_pelagia

I recently purchased Yanmar impellers with the NEW part number (they were not old stock) and YES they have the threaded part.

Same experience here. Was the non-threaded impeller purchased from somewhere other than a Yanmar distributor? Plenty of counterfeit parts to be found on eBay and Amazon. Also, only one side is threaded.

[Captain Bill]

Originally Posted by pcmm

I've Had sinilar experience. Its temping to use a non OEM impeller, specially since the cost savings is significant! Its tough droping $120 for a single impeller, vs $35 for an other brand. But the performance difference is significant!

$120? This has not been my experience. I have never paid significantly more for a Yanmar impeller for my 3jh3ce's than a non-Yanmar version. With a little effort online I have often found them for less than the non-brand. The new replacement versions for my engines are readily available for $35 and I even found them listed in the high 20's. Oddly enough for those interested I got a Yanmar branded impeller a couple of years ago that had Johnson 1027B imprinted on it. It was threaded and still in the Yanmar bag labeled 129670-42531, so I doubt it was a knockoff.

[SVTatia]

Originally Posted by Captain Bill

$120? ... Oddly enough for those interested I got a Yanmar branded impeller a couple of years ago that had Johnson 1027B imprinted on it. It was threaded and still in the Yanmar bag labeled 129670-42531, so I doubt it was a knockoff.

I doubt Yanmar makes impellers, most likely not even the water pump.
This issue can occur with any after-market part, it's up to us to do the due diligence on the equivalents and get the proper fit, or pay the absurd markup for the rebrand to another manufacturer's product.

[sailorboy1]

Originally Posted by pcmm

I wish they still had the thread! the one with the thread ha been "superceded" by one that doesn't have a thread any longer! but I've got a way around that problem now. Hose pipe pliers. reach in and grab the impeller. Actually easier than the OEM puller!

just got 1 last week with the threads for my 4jh3 FOR $30

https://www.ebay.com/itm/115573474002

[pcmm]

Originally Posted by sailorboy1

just got 1 last week with the threads for my 4jh3 FOR $30

https://www.ebay.com/itm/115573474002

We're talking about the correct OEM impellers not the knock-offs which for some reason have 12 vanes instaed of 9, the 12 vane ones that tend to cause issues. And yes, where I an genuine OEM Yanmar impellers for a 4JH engine do cost $120 each It really sucks but it costs what it costs!!

[sailorboy1]

Originally Posted by pcmm

We're talking about the correct OEM impellers not the knock-offs which for some reason have 12 vanes instaed of 9, the 12 vane ones that tend to cause issues. And yes, where I an genuine OEM Yanmar impellers for a 4JH engine do cost $120 each It really sucks but it costs what it costs!!

OK

https://www.ebay.com/itm/15566597866...pid=7044151371