Late model 4JH4-TE Owners - mixing elbow

[Dartanyon]

Hey there, I know it's been discussed, and I've read everything there is to find using a custom search. However it is still leaving me with questions.

So, if you'd indulge me, I'd like to ask about Yanmar 4JH4-TE mixing elbows again.

We've got a new-ish 4JH4-TE (build date August 2011) it is of the family (according to the labels) of RCD 4JH4-TX2. From what I can tell it's of the most recent design. It has 588 hours on the clock, and I'm going through the periodic maintenance for 500 hours.

I do not have the manual that came with the engine, but one downloaded from the internet, and it says to REPLACE the exhaust mixing elbow every 500 hours or 2 years which ever come first. As a Yanmar part these things go for $700. In theory I should be purchasing my 3rd new one right about now (every two years).

I've read through an exhaustive number of posts on the internet. With all sorts of yanmar owners changing out there mixing elbows, but none of them have been 4JH4-TE owners that seem to have the big cube style mixing elbow, everyone seems to have the older "U" style. I've found ONE post about the big cube mixing elbow where someone refers to this style as bomb proof and will outlast the engine, and that there is no reason to replace it.

What's the definitive word on these big cube mixing elbows?

[savoir]

Why not start by taking the old one off and giving it a clean ? You will be looking for pitting. The elbow on my 4JH3 should last 1000 hours and maybe yours will too.

[Sailmonkey]

I believe the big cube mixers are bronze and won't require any maintenance unless they become clogged.
I would leave it alone and concentrate on other tasks....like sailing or napping.

[Dartanyon]

You're right of course, I should be starting with a cleaning and inspection. I should say that the engine is running like a top, and is showing no performance problems what so ever. It all just stems from the yanmar recommendation of replace every 2 years.

More importantly any work will definitely take place after all required naps and sails.

Here is the mixing elbow in question.

[ccannan]

I have a 4JH2-HTE. The picture of your mixer elbow looks similar to mine. My elbow is made of aluminium, not bronze. Mine hasn't been removed, cleaned, or replaced in 15 years. Knock on wood, no leaks yet, but I do own one spare.

[SailRedemption]

Originally Posted by Dartanyon

Hey there, I know it's been discussed, and I've read everything there is to find using a custom search. However it is still leaving me with questions.

So, if you'd indulge me, I'd like to ask about Yanmar 4JH4-TE mixing elbows again.

We've got a new-ish 4JH4-TE (build date August 2011) it is of the family (according to the labels) of RCD 4JH4-TX2. From what I can tell it's of the most recent design. It has 588 hours on the clock, and I'm going through the periodic maintenance for 500 hours.

I do not have the manual that came with the engine, but one downloaded from the internet, and it says to REPLACE the exhaust mixing elbow every 500 hours or 2 years which ever come first. As a Yanmar part these things go for $700. In theory I should be purchasing my 3rd new one right about now (every two years).

I've read through an exhaustive number of posts on the internet. With all sorts of yanmar owners changing out there mixing elbows, but none of them have been 4JH4-TE owners that seem to have the big cube style mixing elbow, everyone seems to have the older "U" style. I've found ONE post about the big cube mixing elbow where someone refers to this style as bomb proof and will outlast the engine, and that there is no reason to replace it.

What's the definitive word on these big cube mixing elbows?

I have all manuals(operating, installation, service) for our engines if you want them. I had them printed at office depot on nice paper and in a spiral book. I'll look tomorrow in them and see what they say.

[Captsteve53]

Doubt very much that the mixing elbow is Bronze (be nice if they were!) more like Aluminium or cast steel/iron , just scratch it and get the answer, if the manual says replace at certain hours they are covering their back sides against claims from owners that get an engine full of sea water,

Saying that I have seen some last as the previous post 10 years and above but called out to try and un freeze a locked engine after 4 years (caused by leaking riser/mixing elbow), Guys that say take them off and check are missing the point!, they normally corrode out from the inside of the chamber (the part you cannot see into clearly in most cases). The issue is that if regular running they are normally OK for a longer period, its when they sit for longer periods they corrode quicker and let you down at the worst time, in closing it is one of the most under reported cause of engine failure around,

I have found a company in the UK that will manufacture custom risers and stock common brands made in 316 SS , 304 GRADE is really not much better than original manufacturers design material, the best if you can find is 321 grade designed for hot water/high corrosion areas.

Cheers Steve

[Zai]

Try HDI Marine, they cast 316 stainless ones and are reasonably priced.

HDI Marine – Parts For Volvo Penta, Yanmar & Detroit Diesel

[Sailmonkey]

Originally Posted by Captsteve53

Doubt very much that the mixing elbow is Bronze (be nice if they were!) more like Aluminium or cast steel/iron :

Proof that I've not lost my marbles!!!

http://www.boatpartsandspares.co.uk/...bow-1730-p.asp

The bronze elbow!! However it's says it's for non turbo models......there may be an equivalent for turbo models.

[Dartanyon]

Thanks for the help all! I'm feeling a little less like I have been ignoring my engine.

• First - get all of my napping & sailing done.
• Second - figure out what the elbow is made of.
• Third - pull it off and give it a good inspection and cleaning
• Forth - take Yanmar's recommendation of replacing every 2 years with a large grain of salt and a dose of common sense.

@SailRedemption I'd really appreciate you taking a look in the specific manual. Particularly in the Periodic Maintenance section in the back right before the specs. I read it in the 500 Hours section.

Originally Posted by SailRedemption

I have all manuals(operating, installation, service) for our engines if you want them. I had them printed at office depot on nice paper and in a spiral book. I'll look tomorrow in them and see what they say.

[a64pilot]

Originally Posted by Sailmonkey

I believe the big cube mixers are bronze and won't require any maintenance unless they become clogged.
I would leave it alone and concentrate on other tasks....like sailing or napping.

My ancient non turbo 4JHE has the cube elbow that is indeed bronze.

I do not know if all cube shaped elbows are bronze or not though

[Sailmonkey]

Originally Posted by a64pilot

My ancient non turbo 4JHE has the cube elbow that is indeed bronze.

I do not know if all cube shaped elbows are bronze or not though

I've furthered my googling......it seems the turbo cubes are cast aluminium or iron.

[Xpress]

I had a 4JH2 turbo with the standard factory elbow and cooling water inlet fed by a vented riser. The vent, which in installation instructions was to be led well above waterline, looped up and then down to the top of a cockpit drain. The drain was blocked by an unknown object, below the gate valve. Result: water under pressure down to the elbow and hydrolock. The installer of the new 4JH4 insisted on a custom made elbow (316 stainless) which he says will last much longer than the factory elbow. It loops in a "U" above the engine and the cooling water joins it well below the engine exhaust port . Thereon to the waterlock and loop. You might like to consider that option if you have to replace the elbow.

[transmitterdan]

I have the fabricated U shaped stainless steel mixing elbow on non-turbo 4JH3E. I remove and inspect every other year. No issues yet after 1,500 hrs. I have no idea why they use the square block units when the U shaped stainless one is so simple and rugged.

[flyingfin]

You dont need to replace every two years, however you should remove and inspect every two years just to ensure that when you do need to replace it the bolts will come out without a cutting torch or drill. Hand sand both surfaces with a thick plate of glass and replace the gasket if all passages are clear. A bath of phosphoric acid squirted into the passage ways will help remove rust from a cast iron elbow. But remember that salt water and raw steel dont mix, and salt water always wins