Requests for tips to remove impeller on 4JH Yanmar

[noelex 77]

Originally Posted by sailcrazy

Ours does not have the threaded end, it just slips onto the flat-sided shaft.

The thread is on the impeller itself, not the shaft. If you want this feature you need to make sure you always buy an impeller with this thread.

If you are completely removing the water pump it does not make much difference, but when dealing with the pump in situ the threaded impellers are much easier to remove.

[Coltrek]

I feel your pain, went through this last May. I can't remember exactly how I got it out, but it was a couple excruciating hours. It helps to have patience. I think I did like a previous suggestion, and used two small vice grips with jaws like a Garr Pike. For the longest time I thought nothing was happening, but eventually I could see it was moving a couple thousands at a time, pulling one side, then the other. I didn't know about the impellers with internal threads at the top, that is a good Idea. I wish Globe Impeller used that extraction method, I really like their urethane impellers.

[sailcrazy]

We've always just bought the impeller the parts book specifies...genuine Yanmar, as per the parts dealer...but w/o the threads. IF...Yanmar has a compatible impeller, with threads, why is it not listed as a suitable sub?? Even though it is truely a PITA, I think I'll stick with the called for part no.

[noelex 77]

Originally Posted by sailcrazy

Even though it is truely a PITA, I think I'll stick with the called for part no.

Yanmar offer both threaded and non threaded impellers. Of course either can be used, but it is well worth the trouble to source the threaded version as it makes removing the impeller much easier.

Threaded impellers are a genuine Yanmar part. See post #26.

You also need the Yanmar impeller tool (which is nothing more than an internal and external threaded nut together with a bolt). This is supplied with all new engines, but unfortunately it is sometimes lost because it looks like an ordinary nut and bolt.

Below is the diagram from the Yanmar engine manual on impeller extraction. Winding the central bolt pushes out the impeller without any fuss, or damage to the impeller.

[Boatwright]

Originally Posted by skipperpete

I can’t say for sure but I have a feeling that it would be easier to remove the pump to extract the impeller. It really does look like the shaft has been damaged and if so, it will be practically impossible to draw the impeller (and if you did manage to drag the old hub off the shaft) , dressing the end of the spline to fit a new impeller would be a real challenge in that tight space. Kudos for being kind to the oring groove in the housing by not trying to lever the impeller off with a couple of screwdrivers.

Try the greasing/rotation method suggested with the duck-billed vice grips.

If that fails, remove the pump -- 4 bolts and not that hard to do. This will also give you the opportunity to inspect/service the drive shaft and bushing which could be worn. Rebuild parts for these pumps are readily available. As others have suggested get the genuine OEM parts; it's a false economy to by cheap Chinese knock-offs. If you lack tools, any good engine repair machine shop will do the actual bushing replacement for a few dollars.

[David Mathis]

Had one somewhat similar to this a few years ago that defied almost all attempts to remove it. Finally, a wood chisel was used to cut and remove the straight vanes then the engine was bumped with the starter to rotate the impeller 180. The vanes that had been compressed were now straight and the section with the vanes removed was aligned with the cam area which lessened the pressure on the shaft. It still would not slide off so a punch and hammer were used to tap the impeller (stay away from the shaft) to break free the crud that was holding it. After a couple taps, the puller worked and the impeller came free. The shaft was cleaned with 400 grit then Never-seize was applied before installing the new impeller.



The photo you attached shows what appears to be a deformed shaft due to impact, perhaps a hammer strike. If this happened, it will be almost impossible to remove the impeller unless the deformed part of the shaft is machined to bring the shaft back to the original diameter. If this is the case, remove the housing to allow better access. You might be able to remove the damage with a small Dremmel tool grinding wheel. If not, just get a new housing or even better, get a new pump with the impeller already installed.

[noelex 77]

Originally Posted by David Mathis

The photo you attached shows what appears to be a deformed shaft due to impact, perhaps a hammer strike. If this happened, it will be almost impossible to remove the impeller unless the deformed part of the shaft is machined to bring the shaft back to the original diameter.

I still think this is the fundamental problem.

[Traumerei]

The Yanmar puller is awesome. Simple and easy to use especially in confined spaces.unfortunately, not all impellers work with it. But with that said have you tried a conventional puller?

[skipperpete]

At least 2 production boat models designers have completely ignored port side access, One of the Wauqiez’s with the engine under the cabin sole at the foot of the companionway and one of the Hunters with a similar engine location. Changing or simply inspecting an impeller on either of these is a hard slog, alternator off first, mirror on a stick and skinned knuckles all while crouching in various yoga positions above a potentially hot engine for as long as 2 hours.
An even tighter work space is on the 3JH series with way less distance between the pump and starter motor but fortunately these engines are usually in Catamarans with good all round access.
I would advise against the use of a pair of screwdrivers to lever out the impeller with the pump housing as the pivot point, the oring groove is remarkably fragile at the thinnest sections and will break off at the lever fulcrum. If this happens and there’s not enough support for the Oring, the only option is to superglue the oring or use a gasket..... forever!

[hpeer]

The thread reminds me how remarkably lucky I am with my fully removable, full length access panels on both sides.

[toddster8]

I've been procrastinating this job on a 3JH in a J/42. Only about 2 1/2" clearance to the starter! Just slightly more than the width of the impeller itself. Can't remove the pump - engine mount blocks the bolts. No puller threads on the old or the new impeller. And there wouldn't be room for it if they did. Access is split between two hatches - one in the shower and one inside the vanity. Extremely painful to get in there.
Once I get started, I'm afraid the motor will be incapacitated for an extended period, waiting for parts, special tools, etc. Or it will end up in some state that requires a boatyard...

[Icarus]

Originally Posted by JSurr

Hello all, I am reaching out in hopes that someone could give me some advice on how to remove a seized impeller from an 4JH Yanmar. It is on an Irwin 43 that engineers found humorous to have the pump behind an 8" partition and a starter thats 6" away that limits the access.

I have tried plumbers pliers, straight and curved needle nose and spent $130 on a Jabsco impeller puller that just slides off. I have ripped off all but one impeller blade in the attempt of getting it out.

I am trying to avoid having to pull the pump because, again insane design, I have to remove an engine mount to get to 2 of the 4 bolts on the pump.

Has anybody ever run into this before and how did you remove the impeller?



Thanx in advanced

Use a couple of short screw drivers and leaver the impeller out of the housing.

[Icarus]

Originally Posted by Scubaseas

two flat blade screw drivers. 180* opposite. Push into impeller and push down equally at the same time. Careful not to deform where the o-ring goes. All you need to do is to get it "rocking" on the shaft and it'll pull right up.

#9 above works too.

As others pointed out replace with OE style with the 18X1.0 mm internal thread so you can use a proper puller.

Use synthetic grease on the shaft to impeller space on install Do not use petroleum grease. Super Lube synthetic works great.

Indeed...

[nonav]

Removing the water pump">raw water pump makes this job a piece of cake, and saves a lot of cursing.

You’ll need new gaskets all around, and need to be gentle with the impregnated paper as it’s a bit brittle.

Synthetic grease on the shaft is always a good idea, and load the housing/impeller with Dawn when reinstalling.

You’ll see bubbles in the discharge water as well as avoid damage to a dry impeller.

[Photonsailor]

Just athought....
I have a 4JH2-UTE with similar awkwardly positioned impeller. Previously had an older 2cyl Volvo. When changing the impeller on the Volvo I always was very careful to simultaneously press inward on the axis with same force as when pulling out the impeller. Reason, first time I did not push on the axis, the axis was also pulled outward with the darn impeller! I stopped in time. I am guessing there must be some kind of sealing bushing that might be compromised if pulled out, with possible seawater ingress into engine oil?
Therefore, I am very careful to always push against the axis when pulling the impeller on my Yanmar, just in case. That is incidentally what the pullers also do.
Just my two cents, maybe irrelevant?