Seawater Impeller Change on Yanmar 4JH

[carlfmiller]

I cannot find this subject in a forum search--but sorry if it is covered already.

New owner of boat with Yanmar 4JH (44HP), looking to replace the seawater impeller just because I don't know its age or condition. In this Lord Nelson 35, I have only top and front access to the motor- and some limited side access, and see on the port-side Yanmar drawing the seawater pump cover plate faces aft, and is hidden behind the alternator. I am not near the boat this minute to actually look at it, (I have photo taken from front) but I am wondering if somebody can describe the accessibility of the seawater pump's cover plate? The space between the cover plate and the starter motor looks pretty tight on the drawing. Any special tricks like having to remove the alternator or anything that would make what should be easy into a difficult job?

Thanks for any advice (I know... if it ain't broke, don't fix it...but on my other boat with 3QM30 the seawater pump impeller was the most frequent failure point if the whole system.)

Carl in Hawaii

[a64pilot]

Nothing to it, four bolts if memory serves, then just pull it out. No need to remove anything.
I put a zip tie on the new one to bend the blades to make install easier.
I have to pretty much tear old one up to remove with needle nose pliers, there is a tool, but I don't use factory impellers so tool won't work for me

[LeaseOnLife]

Yes, access can be a pain, and sometimes the impeller doesn't give up that easy. Please disconnect the starter battery to avoid an accidental short when fighting with the impeller.

90 degrees needle nose pliers make it a bit easier to grab the impeller:

DIY: The All-Purpose Impeller Puller - Sail Magazine

Or one like this: IMPELLER PULLER

Dirk

[jcapo]

Plenty of room between the starter and the water pump cover but you do need side access. Four small hex head bolts, I forget the size, secure the cover.

I use a pair of channel locks that pretty much have parallel jaws when opened to grab the impeller with pressure on both sides of the shaft.

Access to my 4JH water pump is through a cabin sole hatch, across the top of a water tank, and then underneath a cabin sole stringer. I can touch the pump or see it but not both at the same time.

I like the ty-wrap idea.

[jstevens]

Here are pictures of the water pump">raw water pump and alternator on my 4JH4-AE before installation.

http://www.svsarah.com/Sarah/Images/...ne%20Front.JPG
http://www.svsarah.com/Sarah/Images/...ter%20Pump.JPG

Access is not a problem if it is a conventional installation and this is the forward end of the engine. My installation uses a V-Drive and this is the aft end of the engine requiring me to lay over the top to get access. Even then it just a awkward process, access is not a problem.

John

[jcapo]

Looks like the newer 4JH series mounts the pump with the impeller facing forward rather than aft. That makes changing an impeller a LOT easier.

[pcmm]

Originally Posted by jstevens

Here are pictures of the raw water pump and alternator on my 4JH4-AE before installation.

http://www.svsarah.com/Sarah/Images/...ne%20Front.JPG
http://www.svsarah.com/Sarah/Images/...ter%20Pump.JPG

Access is not a problem if it is a conventional installation and this is the forward end of the engine. My installation uses a V-Drive and this is the aft end of the engine requiring me to lay over the top to get access. Even then it just a awkward process, access is not a problem.

John

looks like your 4JH has had its seawater pump reversed. mine (stock) is on the other side of the timing gear, tucked under the alternator. still easy access, but then I can sit in my engine room fairly comfortably to access the engine!

[Jeanneau 45.2]

I have a 4JH3-TE with the same limited access to the impeller issue. Do yourself a favor and buy OEM impellers with the threaded insert. With the Yanmar jack screw tool, removal is a breeze. Worth the extra cost of the OEM part, especially if it prevents collateral damage to the alternator.

[Steadman Uhlich]

Originally Posted by jstevens

Here are pictures of the raw water pump and alternator on my 4JH4-AE before installation.

http://www.svsarah.com/Sarah/Images/...ne%20Front.JPG
http://www.svsarah.com/Sarah/Images/...ter%20Pump.JPG

Access is not a problem if it is a conventional installation and this is the forward end of the engine. My installation uses a V-Drive and this is the aft end of the engine requiring me to lay over the top to get access. Even then it just a awkward process, access is not a problem.

John

The photos help. Thanks for posting them. .
It sure is nice to see such a clean (new) engine. Very nice looking piece of gear.

[Captain Bill]

Originally Posted by Jeanneau 45.2

I have a 4JH3-TE with the same limited access to the impeller issue. Do yourself a favor and buy OEM impellers with the threaded insert. With the Yanmar jack screw tool, removal is a breeze. Worth the extra cost of the OEM part, especially if it prevents collateral damage to the alternator.

I completely agree, and if you shop around online you can often find the OEM version at the same price as the aftermarket impeller without the threads. The removal tool works like a charm and does not require much room to operate. I have a pair of long handled 90 degree needle nose pliers and even though I have plenty of room for access in my engine rooms the Yanmar tool is easier.

[hpeer]

Originally Posted by Jeanneau 45.2

I have a 4JH3-TE with the same limited access to the impeller issue. Do yourself a favor and buy OEM impellers with the threaded insert. With the Yanmar jack screw tool, removal is a breeze. Worth the extra cost of the OEM part, especially if it prevents collateral damage to the alternator.

I have great side access and completly agree with the above.

Just think about having to replace the impeller when off shore in a seaway. It's a no brainer.

[boeing1]

change one on a IP, with pump facing aft, not much room, can be difficult if the impeller does not want to come out, hate to have to change one going down the ICW

[jhulmer]

Originally Posted by Jeanneau 45.2

I have a 4JH3-TE with the same limited access to the impeller issue. Do yourself a favor and buy OEM impellers with the threaded insert. With the Yanmar jack screw tool, removal is a breeze. Worth the extra cost of the OEM part, especially if it prevents collateral damage to the alternator.

I agree - I have the same engine, makes this much easier.

[rmez]

There are impeller pullers, for example one sold by Amazonhttps://www.amazon.com/Jabsco-50070-.../dp/B000O8B1SS
That fits in between the pump and starter (just) on my 4JH2E in my Island Packet 380. You have to lie on your side and access through a smallish panel...no fun.

I"m not familiar with the impellers with threaded inserts..any reference please?
--Reuben

[Safari38LH]

Originally Posted by Jeanneau 45.2

I have a 4JH3-TE with the same limited access to the impeller issue. Do yourself a favor and buy OEM impellers with the threaded insert. With the Yanmar jack screw tool, removal is a breeze. Worth the extra cost of the OEM part, especially if it prevents collateral damage to the alternator.

I have a 4JH2E and unfortunately the factory impellers for this engine do not have a thread. I do have an impeller puller which has two arms which grab the impeller and a thread to pull it out. Works great.