Impeller change on Yanmar 4JH3-TE

[Dockhead]

Originally Posted by goboatingnow

Why do yanmar turn the water pump plate towards the engine body. I hate , really hate that

My little Volvo has a gear pump and the plate faces outwards , piece of cake

In my yanmar I always ended up taking the whole pump off

Long ago I bought both sizes of the Jabsco pullers. Best thing ever

Putting then back I pre bend the tines in the correct direction and secure with a tie wrap. Bit of washing up liquid and hey presto , easy peasy, the tie wrap pops off as the impeller slots home.

There is no "correct direction" for the impeller blades; they flip back and forth with ease. Try turning an uninstalled water pump">raw water pump with the cover off it, in this direction then the other, and you'll see.


As to which direction the raw water pump should face -- I hate that mine backs up on my starter, but for me it would be even worse facing forward, as I have reasonable access to the sides and aft end of the engine but poor access to the front.



What would be really nice is if the engine makers would put their raw water pumps on bevel gears facing OUT towards the side, or top of the engine. Wouldn't that be nice? Once can dream, I guess.

[LittleWing77]

Originally Posted by adjo

Bad Tip (above).

DO insert the vanes in the right direction. They will usually be OK, but a 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.

My understanding, too, is that there's a right way for an impeller to go in.

I've always liked Gord May's signature quote:

<<If you didn't have the time or money to do it right in the first place, when will you get the time/money to fix it?>>

Fair winds,
LittleWing77

[Bellinghamster]

Yanmar seems to have flipped the raw water pump from back to font then back. I've got a 2018 4JH4-TE and it's behind the timing cover, which, as someone else mentioned, requires removal of the forward engine mount to remove the pump.

Seriously, how hard would it have been to provision for both mounting arrangements, using a cover plate for the unused side? Some installations have good front access, some have good side access. Convertible would have been awesome.

I wonder if a front timing cover from a year with a front mounted pump would fit? Unfortunately, lan expensive proposition with Yanmar pricing for the few times it needs changing.

[sail sfbay]

Originally Posted by S/V Reveille

New-to-me boat with a 75 HP Yanmar turbo diesel, a 2001 4JH3-TE..........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?..........

Same engine on my Hunter 46 but poor acsess to the water pump. Might have to remove the pump to replace the impeller. Similar design engine on my Hunter 386 required disconnecting the transmission, rotating the alternator, disconnecting front motor mounts and jacking up the front engine to get access to it.