Yanmar 4jh3-TE stopped with a bang!

[k7cej]

Our Outbound 44 s/v Sequoia just suffered an engine failure while motoring down the Columbia River. There was a loud bang, about 1 second of a hiss (sounding like a punctured pressure vessel) and the motor stopped dead. There was no smoke, fire, or obvious external damage. After getting the boat under control (mid-channel, no wind, but fortunately no traffic)., I tried starting the engine, which to my surprise started. NO obvious clatter, but ran rough with lots of white exhaust smoke and wouldn't throttle up very far. The oil looks clean with no sign of water.
The engine has about 4300 hrs, wasn't burning oil.
I am waiting for a mechanic to have a first look, but I would love to hear your experienced speculation of the possible failure mode.
ps. We have over 40000 sea miles, both Pacific and Atlantic crossings inSequoia and this is the first time we've had any engine problems except a blocked heat exchanger. Also the first time to be towed!

[Bellinghamster]

Seized or broken turbo, maybe? Easy to check - pull the air intake filter off and turn the turbo with your fingers. (or the exhaust outlet from the turbo if you can't get your fingers into the intake side). Obviously do this with the engine OFF.

Are you sure you didn't simply blow a hose off between the turbo and the intake?

It doesn't seem like either of those would cause the engine to stall, but either could make the noise you described and result in low power/smoke if the engine isn't being stuffed full of air like it was meant to be from the turbo.

[Ericson38]

Originally Posted by k7cej

Our Outbound 44 s/v Sequoia just suffered an engine failure while motoring down the Columbia River. There was a loud bang, about 1 second of a hiss (sounding like a punctured pressure vessel) and the motor stopped dead. There was no smoke, fire, or obvious external damage. After getting the boat under control (mid-channel, no wind, but fortunately no traffic)., I tried starting the engine, which to my surprise started. NO obvious clatter, but ran rough with lots of white exhaust smoke and wouldn't throttle up very far. The oil looks clean with no sign of water.
The engine has about 4300 hrs, wasn't burning oil.
I am waiting for a mechanic to have a first look, but I would love to hear your experienced speculation of the possible failure mode.
ps. We have over 40000 sea miles, both Pacific and Atlantic crossings inSequoia and this is the first time we've had any engine problems except a blocked heat exchanger. Also the first time to be towed!

Sounds to me like a [possible] blown head gasket. Does the exhaust have a pulse sound that is in synch with vibration. If so, weak cylinder, maybe head gasket. I just got done replacing our turbo on the 4JH2-HTE, and also went through the heat exchanger (2300 hours). Can't think off hand what else can give a hiss like that, and a pop, except the head gasket failing between adjacent cylinders. Compression test for sure coming shortly. Would be down on power, and white steam in exhaust could be from coolant vaporizing. Would not get into oil. I had an old Goldwing that went through this very failure, and oil was perfect.

Our turbo failure resulted in very black smoke (rich) under about 1/2 throttle or more, but still very smooth running.

[skipperpete]

Fouled propeller would be my first thought ...BUT ... if it starts and runs badly out of gear then it will be an engine or reduction gear fault.

[k7cej]

Thanks for the thoughts, guys! My first thought was a blown head gasket, leading to hydrolock. If the blowout was between cylinders, with no oil passages involved, that might explain the symptoms. The mechanic is due on Monday...I'll post again when he has had a first look.
If it is a blown head gasket and nothing got bent, I would think it would be much less costly. If I have to replace the engine, the current model is the 4jh4-te and I don't know if its fastenings are the same. Also, I have an Autoprop (which has been great) and it is designed for the specific torque curve, and might likely need new blades ($$).
Craig

[Ericson38]

Originally Posted by k7cej

Thanks for the thoughts, guys! My first thought was a blown head gasket, leading to hydrolock. If the blowout was between cylinders, with no oil passages involved, that might explain the symptoms. The mechanic is due on Monday...I'll post again when he has had a first look.
If it is a blown head gasket and nothing got bent, I would think it would be much less costly. If I have to replace the engine, the current model is the 4jh4-te and I don't know if its fastenings are the same. Also, I have an Autoprop (which has been great) and it is designed for the specific torque curve, and might likely need new blades ($$).
Craig

The 4JH is a 1.6 liter. The 4JH2 is a 1.8 liter, same block. The 4JH3 is 2.0 liter, same block. The 4JH4 is also a 2.0 liter, with 4 valve head. The 4JH5 is common rail (electronically controlled injectors with ECU).

[k7cej]

I was told by a dealer today that the current successor to the 4jh3-te is the 4JH80, which has a common rail system. I have no idea if it uses the same location engine mounts, or if the transmission geometry is the same. He also said that my KMH4a transmission was lightly built and designed for a 2000 hours lifetime. News to me.
>>Actually it may be a KM4A2 transmission; I'll have to check<<

[skipperpete]

News to me too, it’s probably the dealers subtle way of ensuring you buy the “ package” rather than a bobtail engine and using your existing KMH4A.

[Brunton's Propellers]

Originally Posted by k7cej

Thanks for the thoughts, guys! My first thought was a blown head gasket, leading to hydrolock. If the blowout was between cylinders, with no oil passages involved, that might explain the symptoms. The mechanic is due on Monday...I'll post again when he has had a first look.
If it is a blown head gasket and nothing got bent, I would think it would be much less costly. If I have to replace the engine, the current model is the 4jh4-te and I don't know if its fastenings are the same. Also, I have an Autoprop (which has been great) and it is designed for the specific torque curve, and might likely need new blades ($$).
Craig

Drop us a line if you need your Autoprop servicing or checking. sales@bruntons-propellers.com

[GreenWave]

I call BS on that transmissions advice. Change the oil and they should last as long as an engine which normally is longer than yours.

[MBWhite]

Well, I try yo give an optimistic outcome here!


So you're motoring away and you hear a "BANG!" then a hiss.


Did the bang sound like a balloon or M80 as opposed to dropping an anvil from a ladder on to a car?



Could be as simple (read cheap!) as a turbo boot blowing off. If you are up to it, give all the intake hose connections a good look AND feel by running your hands all around the flex hoses on the intake side between the turbo and the intake. Try to feel for bulging and then feel all the clamps to make certain none have failed. If you can get the engine started again you may be able to hear it hiss and narrow it down but usually a good visual inspection will show you if you've had an intake flex hose burst.

[Ericson38]

Originally Posted by MBWhite

Well, I try yo give an optimistic outcome here!


So you're motoring away and you hear a "BANG!" then a hiss.


Did the bang sound like a balloon or M80 as opposed to dropping an anvil from a ladder on to a car?



Could be as simple (read cheap!) as a turbo boot blowing off. If you are up to it, give all the intake hose connections a good look AND feel by running your hands all around the flex hoses on the intake side between the turbo and the intake. Try to feel for bulging and then feel all the clamps to make certain none have failed. If you can get the engine started again you may be able to hear it hiss and narrow it down but usually a good visual inspection will show you if you've had an intake flex hose burst.

That won't cause white smoke or rough running. It only would cause a hiss and be down on power (and black smoke).

[Ericson38]

Originally Posted by k7cej

I was told by a dealer today that the current successor to the 4jh3-te is the 4JH80, which has a common rail system. I have no idea if it uses the same location engine mounts, or if the transmission geometry is the same. He also said that my KMH4a transmission was lightly built and designed for a 2000 hours lifetime. News to me.
>>Actually it may be a KM4A2 transmission; I'll have to check<<

Mine's a KM4A. Not heard of KMH4A.

[noelex 77]

Originally Posted by Ericson38

Not heard of KMH4A.

KMH4A is the hydraulic transmission option used on mid sized Yanmar marine engines.

[k7cej]

To close the loop on this story:
It turns out the bang and hiss were the sounds made by my new Fireboy MA0100NVC engine room extinguisher going off. It discharged in less than 1 second and killed the engine, probably by displacing the oxygen. When I had tried to restart the engine, the rough running and voluminous white smoke were no doubt unburned fuel.
It was certainly my fault for not catching that it had discharged. It uses the new 3M chemical Novec 1230, which is claimed to have absolutely no negative environmental affect. It works by first rapidly lowering the temperature (they claim it will give you freeze burns if you are nearby) then further breaking down to compounds that inhibit combustion. I opened the engine access within 5 seconds of the event and saw no trace of chemical, fog, or dust.
There is no way the engine room was at a high enough temperature to trigger the bottle (175F) so I have concluded that its mechanism somehow failed and I will be submitting it for warranty replacement.
The mechanic who inspected the engine said it is possible the injectors might have been damaged, so we will pull them for testing and do a compression test while we're at it.
Follow up on the power train: the transmission is a KM4A, 2.63/1 ratio. Fortunately I don't think I will be having to replace the engine!
Craig,
s/v Sequoia