Hydrolocked? Yanmar 4JH2-TE

[Geoff54]

I'm sorry if I fomented some friction here - It was not my intent. We had one person state that this engine can't be bored and one person say the the 4JH series can't be bored. I knew that this wasn't true for this engine and I just wanted to get a definitive answer for anyone reading the thread. I think that we have done that. Thank you.



Hey, how's it going Isaak??

[IsaakOker]

Haha I just typed a real long post and it deleted it asking me to login again 😢

So once again.. Today has been a real slow Sunday.. Finally a day to relax although I should have been working to get this reassembled ASAP.

I'm good Geoff, hope you're doing well too!

Today I only cleaned the block from the outside with a wire brush and some wet sanding to prep for paint.
I also got the elbow cleaned a bit although not much buildup and no visible cracks or anything wrong..

Tomorrow I'm planning on cleaning the head a little, I'll also take the exhaust manifold apart to clean it and put it through acid, should I neutralise the acidity or just by flushing it through fresh water is fine?

I also will probably take the intake manifold of the head as its still on, should I or should I just keep it on there to not replace the gasket?
What would you check if I take it off and how to clean it?

Another doubt I have is what I should do with the turbo. The carbon buildup is very close to not letting the blades spin so should I attempt cleaning it or is it really to delicate to even attempt?

And then, to paint the engine, how hot does the exhaust manifold get? Is 500F Paint enough?

[DeepFrz]

You might want to check out this thread. Especially post #8. Good luck with your rebuild.

http://www.cruisersforum.com/forums/...bo-100605.html

[Wotname]

Originally Posted by CassidyNZ

No I believe the pic of a 3 cyl block is simply there to indicate how the sleeves are removed. The manual does not cover series of models, it is 4JH-specific. If you google Yanmar sleeve kits you’ll find that there are several models that use wet liners and the removal/installation is the same.

OK, thanks for the explanation.

[Geoff54]

Originally Posted by IsaakOker

Haha I just typed a real long post and it deleted it asking me to login again 😢

So once again.. Today has been a real slow Sunday.. Finally a day to relax although I should have been working to get this reassembled ASAP.

I'm good Geoff, hope you're doing well too!

Today I only cleaned the block from the outside with a wire brush and some wet sanding to prep for paint.
I also got the elbow cleaned a bit although not much buildup and no visible cracks or anything wrong..

Tomorrow I'm planning on cleaning the head a little, I'll also take the exhaust manifold apart to clean it and put it through acid, should I neutralise the acidity or just by flushing it through fresh water is fine?

I also will probably take the intake manifold of the head as its still on, should I or should I just keep it on there to not replace the gasket?
What would you check if I take it off and how to clean it?

Another doubt I have is what I should do with the turbo. The carbon buildup is very close to not letting the blades spin so should I attempt cleaning it or is it really to delicate to even attempt?

And then, to paint the engine, how hot does the exhaust manifold get? Is 500F Paint enough?

Hi Isaak

Sorry that I didn't respond, I was out all day yesterday. It's probably way too late by now but....

By using acid on the exhaust manifold, I assume that you mean on the heat exchanger tube stack. I'd only do that if there is a build up that needed it. And I have no idea if this is more or less likely in fresh water. I'd rinse it really thoroughly afterwards, though.

Removing the manifold from the head is really up to you. There wasn't any sign of a leak, right? I expect that you can leave it in place. It's usually cheaper to buy a gasket set so you'll probably have the gasket anyway. Not much to check but it should be flat across the mating surfaces (almost certainly will be) . Just clean the surfaces and clean out any carbon buildup. Or leave it as it is.

As for the turbo, turbos do have tight tolerances but you need advise from someone with more experience. They can be dismantled, cleaned and reassembled with new bearing (if needed) and seals but that not something I have done. There are methods to clean them in place, but I have no idea how safe or effective they are. Can the mechanic that took a look offer any advise?

Not sure about the manifold temp either but you do see entire engines painted after assembly so I imagine regular engine paint is fine.

Have you striped the head? What does it look like?

BTW, I was thinking about when you got the pistons out and they stuck with 10mm sticking up. That would mean that the compression rings had cleared the ridge so it was the oil control ring hanging up. You would have been hammering against the top edge of the skirt rather than the much weaker lands and I know your were careful. I bet they look fine.

Hope you are making good progress.

[a64pilot]

I’d either send the turbo off, or leave it alone.
They are extremely simple devices, but can be easily damaged also, especially the cold side, hot side is pretty robust.

Once the engine is running well, you can “wash” it. Simple procedure, but don’t worry about that now, that an after it’s running thing.

[Shaneesprit]

Ok
If you can’t turn the engine with a bar then I am sorry but it’s seized and need a full rebuild!
As a thought you could try taking out the oil and filling it with Diesel for a day or two. Diesel is the most aggressive oil you will find.
But if you have got to a point where you cannot turn it without the injectors out it cannot Hydro.
Don’t force it - it won’t damage anything as the damage is already done

[Shaneesprit]

When I said filling it with Diesel - I meant the oil sump to the level of the dipstick,
Do not start it in this condition but if you are as lucky as a lottery winner maybe it will turn by hand or starter motor in a day or two
If it does renew the oil and filter with cheap oil before starting and replace oil and filter 5 mins after you get it running

[DeepFrz]

Originally Posted by Shaneesprit

When I said filling it with Diesel - I meant the oil sump to the level of the dipstick,
Do not start it in this condition but if you are as lucky as a lottery winner maybe it will turn by hand or starter motor in a day or two
If it does renew the oil and filter with cheap oil before starting and replace oil and filter 5 mins after you get it running

It would have been nice if you had read the whole thread.

[BruceS]

haha .... it's easy to do though. I nearly got caught a few pages back. When you return to a thread you get taken to the first unread post in that thread & if there are two more pages since then it's easy to miss it.
His heart was in the best place? Look funny filling the sump with diesel if it was sitting on the wharf? lol

[DeepFrz]

Originally Posted by BruceS

haha .... it's easy to do though. I nearly got caught a few pages back. When you return to a thread you get taken to the first unread post in that thread & if there are two more pages since then it's easy to miss it.
His heart was in the best place? Look funny filling the sump with diesel if it was sitting on the wharf? lol

Bruce, thanks for this. I forgot how easy it is to reply to a post in the middle of the thread. My apologies to Shaneesprit.

[Bycrick]

To make you feel more optimistic about your project. About ten years ago, the Yacht Club bought a used 3GM engine for one of our work boats. We had no idea of how many hours and there were vague rumors of being underwater sometime. Two years later (with a historic average of 2000 hours/year), the boat sank. Stayed underwater for several weeks. Finally raised, taken to a "mechanic" who let it sit in the shop for six months. We finally got it back. Thinking that really rebuilding it was a waste of time and money, we did the absolute irreducible minimum of work. Now, some 10k hours later, it’s still running just fine.

[Shaneesprit]

Yeah sorry for that, wouldn’t of replied if I had seen the rest of the thread, you just seemed a bit lost at the point I replied.
With the Turbo
Just use some brake or Carb cleaner if your not having it rebuilt. ( as long as it spins freely )

[Cheechako]

re: turbo.. how much HP is that engine? Do you need the Turbo? Would it produce plenty of HP for your boat size if you remove the turbo? I avoid them like the plague.
There's an old adage: "Buy the lowest HP in the biggest block. That engine will last forever."
So if a company offers an engine line that one block size offers 50-75 HP (75 being turbo) and another block that offers 75-100 HP models. Buy the second one at 75 hp!

[BruceS]

I've been told that some engines won't run properly if you just remove the turbo? I think firstly the injector pump would need adjusting if nothing else.
Of course on electronic motors it'd be impossible as the engine computer would do a hissy fit!
PS. I wouldn't touch the turbo. If it looks & feels like it needs attention then get an expert involved.
Just yesterday I saw the remains of an Isuzu engine that had bits of a turbo through it. Ouch!!
Washing the oil out of the bearing or rubbish INTO it would not be good.