Requests for tips to remove impeller on 4JH Yanmar

[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.

[sailorboy1]

I used to just have the destory the impeller in my 4jh3 to get it out. And it was hard to do.

So I will echo those that have said to get the Yanmar impeller that has the threads and get a puller. Makes the job easy! Remember when installing the new impeller to be sure threads are facing out. From personal experience the impeller works fine the facing the wrong way, but you have to pry it out now.

I always have to take a hose off and move my alternator to get mine out. It is just easier than working around them.

[SailingHarmonie]

On some installs of these I have had luck with crows foot wrenches to remove the hardware securing the pump without taking the motor mount off. Every serious boat mechanic needs a set of those. Certainly worth a look.

You might have noticed that half the posts in response here assume you have a “pull off” impeller and the others assume yours screws off. Kind of important you determine that for yourself. If yours is screwed on you can pull all day long and get nowhere!

[noelex 77]

Originally Posted by SailingHarmonie

You might have noticed that half the posts in response here assume you have a “pull off” impeller and the others assume yours screws off. Kind of important you determine that for yourself. If yours is screwed on you can pull all day long and get nowhere!

They always pull off.

Yanmar make an impeller puller that screws on to the impeller (if it is a genuine Yanmar version), but it still pulls the impeller rather than unscrewing it.

[pcmm]

Originally Posted by sv_pelagia

Just to strongly re-emphasize what has already been stated:

Make sure you replace with a new Yanmar impeller that has the threads which makes the subsequent removal of impeller incredibly easy (using inexpensive Yanmar puller... essentially a bolt within a nut with threads inside and outside). See photos. Attachment 271597
Attachment 271599

Unfortunately the latest part number for the Impeller for the 4JH series engines no longer has a thread that you can use the Yanmar puller with.

[sv_pelagia]

Originally Posted by pcmm

Unfortunately the latest part number for the Impeller for the 4JH series engines no longer has a thread that you can use the Yanmar puller with.

Hmmm... have new Yanmar impeller purchased last May WITH threads.

[RaymondR]

Experienced the same problem and finally got it out by using a battery drill to drill a hole in the brass sleeve into which I could seat a pointed bar and lever it out. I did not drill all the way through the sleeve to avoid damaging the SS shaft.

[pcmm]

Originally Posted by sv_pelagia

Hmmm... have new Yanmar impeller purchased last May WITH threads.

You probably got new old stock. According to my Yanmar distributer the current impeller part # 129470-42532 replaces/supercedes 129470-42531 and 129470-42530.

129470-42532 doesn't have any threads that you can use the Yanmar tool with

[MicHughV]

This will take patience, but I've done this before......grind a hacksaw blade flat on it's end, even grind it thinner, if needed, along it's length for 2-3" or so, enough to fit between the hub and the walls of the impeller housing.
Wrap the rest of the blade with some cloth, so you can grip it with your hand and starting at the top, saw the impeller hub. Once enough material is removed, a thin blade or screwdriver tip is enough to spilt the hub open, making removal easy.

[motion30]

On the jabsco puller. The jaws do not need to get behind the impeller. They dig into the rubber body of the impeller if you tighten the crossbar tight enough.

[noelex 77]

Originally Posted by pcmm

129470-42532 doesn't have any threads that you can use the Yanmar tool with

If you buy Yanmar part:

Impeller Kit 129670-42610

It will have the threads for the impeller extraction tool.

[pcmm]

Originally Posted by noelex 77

If you buy Yanmar part:

Impeller Kit 129670-42610

It will have the threads for the impeller extraction tool.

Interesting. It also has the "old" number of blades 12 instead of 9

[Shrew]

On my Yanmar one of the bolts for the water pump">raw water pump can't be removed without removing an engine mount first. However, you can remove all of the bolts enough to free the pump itself. This allows the one bolt to remain inside of the flange for the pump and giving the pump and bolts clearance to be removed without touching the motor mount.

I like it this way. It's way easier to replace the impellor on a bench.

[sailorboy1]

Last impeller I got this past summer came as a kit with the o-ring and SS bolts with hex heads instead of the screw head

[Scubaseas]

Originally Posted by MicHughV

This will take patience, but I've done this before......grind a hacksaw blade flat on it's end, even grind it thinner, if needed, along it's length for 2-3" or so, enough to fit between the hub and the walls of the impeller housing.
Wrap the rest of the blade with some cloth, so you can grip it with your hand and starting at the top, saw the impeller hub. Once enough material is removed, a thin blade or screwdriver tip is enough to spilt the hub open, making removal easy.

These are faster. Use a scuba tank if you don't have compressed air. I suppose you could modify an oscillating tool blade to work
ahttps://www.northerntool.com/shop/to...9&gclsrc=3p.ds