Impeller change on Yanmar 4JH3-TE

[S/V Reveille]

New-to-me boat with a 75 HP Yanmar turbo diesel, a 2001 4JH3-TE with 4800 hours. I'm trying to do basic maintenance before my first sail, and am having a bear of a time trying to replace the impeller. There has to be something I'm missing... anyone have experience or advice to offer?

The boat has been on the hard for a couple of years (it was winterized) and I'm trying to address the issues most likely to cause a problem. I've changed the oil and oil filter, primary fuel filter, V-belt, Racor filters, etc... I'm thinking that an impeller that has been dry for a couple of years needs to be replaced... Am I missing anything else?

[skipperpete]

Try and find one of these in the toolkit and hope that the impeller is the one with the thread. Throw a bit of soapy water on the impeller blades.
There is a series of things that need to be done to your engine before you touch the starter button beginning with rotating the engine manually and taking the air intake strainer off the turbo and checking to see that it rotates smoothly.
Get everything done before the yard slings up the boat, the list is long.

[wingssail]

Originally Posted by S/V Reveille

New-to-me boat with a 75 HP Yanmar turbo diesel, a 2001 4JH3-TE with 4800 hours. I'm trying to do basic maintenance before my first sail, and am having a bear of a time trying to replace the impeller. There has to be something I'm missing... anyone have experience or advice to offer?

The boat has been on the hard for a couple of years (it was winterized) and I'm trying to address the issues most likely to cause a problem. I've changed the oil and oil filter, primary fuel filter, V-belt, Racor filters, etc... I'm thinking that an impeller that has been dry for a couple of years needs to be replaced... Am I missing anything else?

So you are " having a bear of a time trying to replace the impeller"? I'm presuming you can't get the old one out.

I'd have left it alone until after launching and running the engine, (how much water is expelled?). But since you've apparently started, you need to finish.

This page from a jabsco site gives some guidance.

[Sailor_Al]

I have the 2008 Yanmar 75 HP, 4JH4 TE. I used a puller from Amazon. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[SV__Grace]

Originally Posted by wingssail

This page from a jabsco site gives some guidance.

Great page that answers OP's question. The impeller puller makes the job so much easier.



Mine is in a tight spot at an angle that makes it hard to use anything else, and I had to shorten the bolt on the puller 1/2 inch so it would fit. Works beautifully!


Two tips-


1. Use a zip tie to compress the vanes when installing the new impeller.


2. When installing the new impeller, don't worry about which direction the vanes go, when it starts spinning they will all end up going the right direction.

[raycullum]

I have the same engine and yes it is a bear. It is not the impeller that the problem, it is it's location. There is little room between the housing and the starter making it almost impossible to extract. I have done the same as someone else noted and cut down a gear puller to be able to get it in front of the starter. I actually once removed the alternator to get at it.

Yanmar has finally listened to it's owners and have changed the raw water pump to face forward.

[Stargo]

At some point it may just be easier to take the pump out and deal with the impeller where you can get at it easily. It would also give you an opportunity to have a look at the seals and bearings.

[Scott Berg]

Bayshore Marine makes a custom puller for exactly this reason! https://www.bayshoremarineengines.co...lerpuller.aspx

[sv_pelagia]

As post #2 indicates if/hopefully the impeller is a (relatively) new Yanmar impeller WITH threads, then the simple Yanmar impeller puller (as in the picture) works well/easily in the tiny space.

Whatever, when replacing with a new impeller, be sure to replace with the Yanmar threaded impellor to make future changes MUCH easier

[pcmm]

Originally Posted by Scott Berg

Bayshore Marine makes a custom puller for exactly this reason! https://www.bayshoremarineengines.co...lerpuller.aspx

That "Custom puller" is a common pair of "Hose pliers" everywhere else. That's what I use, works well.

[steve77]

As others have said, the location of the pump makes this a real pain. I would recommend removing the pump from the engine in order to replace the impeller. Before everyone starts saying that's not required, either A) you don't have this engine, or B) you don't remember the first time you tried to replace the impeller.

When I removed my pump, I found several pieces of broken vanes in the pump outlet. It was a great way to clear out the PO's mistakes at the beginning of my ownership.

Even today, I find it just as easy to remove the pump than trying to change the impeller with the pump in place. My Speedseal kit for the engine really was a waste of money. Even with the pump cover off, the impeller is all but inaccessible.

Just remove the pump. Four bolts, and only one is a little difficult.

Cheers!

Steve

[adjo]

[2. When installing the new impeller, don't worry about which direction the vanes go, when it starts spinning they will all end up going the right direction.[/QUOTE]

Bad Tip;
DO insert the vanes in the right direction. They will usually be OK but the vane that is compressed backwards by the cam has to do a double flip in a very small space and can be damaged. This may not be immediately apparent but can lead to premature failure.

It's just as easy to do it right.

[Pleasure II]

I would say it is your heat exchanger. It has been partially blocked by foreign objects.
No sailing in Sydney. We are all in lockdown here
Cheers

[Jeanneau 45.2]

I too have this engine year 2000. I had to remove my water pump and found it necessary to move the engine mount (more below) to allow clearance to back out the pump. The pump is gear driven and must be removed / installed "straight in" otherwise the gear teeth bind and prevent insertion. I'm not sure but I seem to recall also removing the alternator. You need to have a clear view of the block / pump mating flange to ensure the old gasket is entirely removed. So you will need a new gasket and Permatex ... while not everyone agrees with the need to use the Permatex, I find it very helpful in keeping the gasket in place while mating up the pump to the flange.

Do not touch the motor mount stud / nut. Mark / scribe the exact location where the mount is located on the engine bed, then loosen one bolt and remove the second bolt from the engine bed. Use cribbing under the front of the engine block (not oil pan) to raise the engine the tiniest amount (like 0.010"). With the engine weight now off the motor mount, you can now easily remove the four bolts attaching the motor mount bracket to the engine block and swing the motor mount clear of the water pump. Unbolt and pull the water pump.

Reassemble in reverse order, making sure to use the scribe lines to located the mount on the engine bed.

While my method may seem require a lot of unnecessary work, it prevents having to "do over" caused by damaged gasket or misaligned pump gears.

[t380029]

I have a 2005 4JH 3TE and have changed the impeller every other year. I use the Jabsco puller without inserting the T handle (which is too long). I can pull the impeller straight out without a jack screw. I also leave one screw in the cover and rotate it out of the way which makes reassembly much easier. I also bought spare cover screws which I have not ( yet) needed.
This is a blind operation for me so I use a ratcheting box wrench and a socket on a small u joint wrench handle on the cover screws.
I agree with using a zip tie and try to keep proper blade orientation. I also use glycerin to lube the impeller and housing. Also, don’t forget the O ring.
I use my phone to “see” the pump.
I would not like to try changing the impeller while under way, which is why I change it frequently.
Hope this helps.
Mike Bolon