Yanmar 3Jh4E Is Blocked

[Karl Trautmann]

Hi, I'm new in this section, so I have to learn first to use it, with your help, thank you.
My problem: Its a Sailing boat 'Tireme 38'' with a nearly new Yanmar engine
3 JH4E with 600 h running time. To start the new saison I discovered that the
engine is blocked. We took off the gearbox and the engine is still blocked. We
took off the 3 spray nozzles and added some Motoroil. Now we are waiting for a result since 20 h. What can we do more? Thanks for any further adwise.

Karl Trautmann

trautmann.cy <at> gmail <dot> com

[Ex-Calif]

When you say blocked do you mean seized as in the engine wont turn?

How are your trying to turn the engine? With the starter?

Have you taken a large breaker bar and appropriate sized socket and put it on the crankshaft nut and tried to turn it that way?

When you say took off the gearbox do you literally mean separated the gearbox from the engine by unbolting it or put the gear in neutral?

can you see in the injector hole if there is water or rust inside the cylinder?

What kind of engine is it?

Sorry for so many questions.

[Karl Trautmann]

Yanmar engine 3JH4E is blocked?

Ex-Calif thank you for your quick answer.
The engine don't turn. The gearbox is separated by unbolting and there is nothing to see in the injector holes. The opening is too small. We tried to turn the engine with a big screwdriver at the flywheel in the starter hole. There is a 19 mm screw at the crankshaft. We tried with a large breaker, but not to hard in fear to break the screw off.
Perhaps we should add some WD40 or similar in the injector holes? Thank you for you answer.

[sigmasailor]

Sounds like water entered the cylinders somehow. When that happens (and you do not spot it at once) and leave the engine for some time the piston rings and cylinder will rust blocking you engine). It can happen via the exhaust if not properly designed or some bad luck. It can also happen by a bad head gasket or cracked head. The next step would be to remove the cylinder head to further investigate.
It does not sound very good.

[Karl Trautmann]

Yanmar engine 3 JH4E is blocked

thank you sigmasailor for your answer.

The boat was during the winter on the hard and the exhaust is designed by yanmar. so it should be ok. The head gasket could have a leak. We will start to take the engine out and will remove the cylinder head,, so we can see what happens.
thank you for your help. I hope it will be a guarantee case!!!

[Ex-Calif]

If it is going to be warranty I would not do too much more in terms of taking the engine apart. I hope you have a yanmar service shop nearby.

Might be time to get them involved and start finding out what they require to substantiate a claim, if any is possible.

[sigmasailor]

https://www.frenchmarine.com/marine_...ssemblies.aspx
Many things can go wrong here.
Did they allow your boat to sink at the back when it was hauled out?
Could be just some light rust (did you oil it up before leaving for the winter) you will see if you remove the head (fixable without removing the engine?). If you still have guarantee why not let a Yanmar service engineer have a look at it first? Taking the head of is a lot easier than removing the whole engine.

[Chief Engineer]

Have a mechanic take a look at it before you cost yourself more money

[Karl Trautmann]

Yanmar engine is blocked
Thank you for your advise.
We already have contacted yanmar and an mechanic was on board. He said we must take
the engine out. They don't want to work in a small compartment. Perhaps we could ask him to take the head off on board.

[Karl Trautmann]

Yanmar Engine is blockes

The yanmar mechanic took the engine head off and inside was every thing corroded. There must have been water inside, sweet water. We will have to take the engine out and yanmar will investigate what happens.
I will then report again.
Thank you for your help.

Karl

[sigmasailor]

Were all cylinders rusted?
How do you know it was sweet water?
If all cylinders are rusted I still think the exhaust system could be the cause; on the other hand if it was cooling water it could (with some bad luck) flow from cylinder to cylinder via valves and headers.