Attn: 49 & 50 owners

[artboas]

For those of you who haven't had the pleasure of doing so, changing the engine water pump impeller on the Yanmar 4JH-HTBE is a 2-3 hour job;
And that assumes you are sitting at a dock. In rolling seas it would be almost impossible.
Good news:
I've come up with a method to change the impeller in 15 minutes.
I'm working out the details of it, and will post a document once it's done.
The only thing slowing me down is some recent knee surgery.
Once I'm healed, I will be good to go with this.
So, help is on the way.

 

[RHUMB RUNNER]

Very easy to pull the impeller if you have the Yanmar impeller puller ($15). Just move the alternator out of the way.

 

[artboas]

Moving the alternator

Very easy to pull the impeller if you have the Yanmar impeller puller ($15). Just move the alternator out of the way.

Is far from a small job . Is it's not moving it; it's removing it.
Have you done this yourself?

Btw, the yannar tool is. Jackscrew.
You need excellent access to the rear.
Plus, only I works on Yanmar ; not johnson impellers.

 

[KD3PC]

You need excellent access to the rear.

I use the mirror method and a bright light, once you get used to everything being "backwards" it is not too bad.

For sure, would be much tougher in rolling water or a channel. I switched to a speedseal cover on my second seasonal change and never looked back, can almost do it by "feel"

IF you have a spare water pump, it can be easier to swap the whole unit out and then R&R the impeller on the bench. Fewer bolts, but more mess.

Ah, the joys of owning a sailboat. But think of the $200-300 you save by not having the yard doing it and you - KNOWING how it is done, just in case.

 

[Velero49]

I replaced the pump cover with Speed Seal and use a puller no need to remove alternator. you do have to remove the engine cove which is a pain....

 

[Steve Dion]

Bent nose pliers are a big help when r/r the impeller.

We were able to cut an access panel on the port side of the engine compartment which was a big help on our HV'36.

 

[artboas]

No way with boat rolling

I use the mirror method and a bright light, once you get used to everything being "backwards" it is not too bad.

For sure, would be much tougher in rolling water or a channel. I switched to a speedseal cover on my second seasonal change and never looked back, can almost do it by "feel"

IF you have a spare water pump, it can be easier to swap the whole unit out and then R&R the impeller on the bench. Fewer bolts, but more mess.

Ah, the joys of owning a sailboat. But think of the $200-300 you save by not having the yard doing it and you - KNOWING how it is done, just in case.

Working backwards with a mirror, etc., is fine when the boat is dead still.
Even so, there is no way to get around the alternator with the engine sub-floor.
One of the things you should do, (until I publish my fix), is to use socket head cap screws for the cover screws.
That way you can load the screws onto a super-long Allen key, and not lose the screws in the bilge.
Another trick with socket head cap screws is to put a single wrap of masking tape around the screw head to keep it attached to the Allen key. Then once it's partially threaded in, pull back the Allen key & the tape comes right off.
The pump location on this engine , (facing backwards) was a huge oversight by a Yanmar. They have corrected it in their latest engines