'THERE IS SMOKE EVERYWHERE!!' not what you want to hear 40mi offshore....

[cww]

The way my exhaust/engine is setup even if you forced water through the scoop it would just enter the exhaust at the top of the engine room on the downhill slope of the exhaust and exit the boat through the mufflers. This is not a exhaust lift setup. What you are describing just could not physically happen with the exhaust/engines setup the way they are.

I mean, you’re saying that but in the real world it happens, could also be backflow from wave action if that engine wasn’t running. This is not uncommon. Several boats at my old marina on the dock that got the most wave action would stuff soccer balls or whatever was inflatable that would fit in the exhaust ports when they were gone for an extended period. Successive wave action can build up enough water and pressure to force water back up the exhaust into the cylinders if the engine isn’t running.

 

[rustybucket]

I mean, you’re saying that but in the real world it happens, could also be backflow from wave action if that engine wasn’t running. This is not uncommon. Several boats at my old marina on the dock that got the most wave action would stuff soccer balls or whatever was inflatable that would fit in the exhaust ports when they were gone for an extended period. Successive wave action can build up enough water and pressure to force water back up the exhaust into the cylinders if the engine isn’t running.

Yeah, I hear ya, and 100% understand and appreciate what you are saying. But.... on the day all this happened the gulf was like a swimming pool, literally zero waves, flat, glass calm.

 

[cww]

If it were idling, in reverse rotation, without me knowing about it.... How long do you think it would take to seize up a reverse idling engine with no oil or raw water coolant flow?

I have no idea what the answer is, but it would be very interesting to know.

My money is on water backed up into the engine either through the exhaust or it made it past a water pump that had some wear and tear on the cam plate and wasn’t water tight, and that you bent one or more rods for the aft cylinders from hydrolock when you went to start it up. I think the odds of the engine randomly running in reverse when you hit the start button are very close to zero and the odds of it being hydro locked from trolling with that engine off are pretty high.

 

[cww]

Yeah, I hear ya, and 100% understand and appreciate what you are saying. But.... on the day all this happened the gulf was like a swimming pool, literally zero waves, flat, glass calm.

You have to tear it down one way or the other, so it won’t be a mystery for very much longer.

 

[SKYCHENEY]

If it were idling, in reverse rotation, without me knowing about it.... How long do you think it would take to seize up a reverse idling engine with no oil or raw water coolant flow?

I have no idea what the answer is, but it would be very interesting to know.

I would think it wouldn't run long before it would be out of fuel. I'm kinda with CW on this one. I still doubt it ran in reverse.

 

[rustybucket]

My money is on water backed up into the engine either through the exhaust or it made it past a water pump that had some wear and tear on the cam plate and wasn’t water tight, and that you bent one or more rods for the aft cylinders from hydrolock when you went to start it up. I think the odds of the engine randomly running in reverse when you hit the start button are very close to zero and the odds of it being hydro locked from trolling with that engine off are pretty high.

Water getting by the water pump would put the water in the oil right?

So, where did all the smoke come from?

If I'm just hydrolocked (and bent rods) why is the engine still seized now that we have the heads off? A hydrolocked engine should have spun free as soon as I got the injectors out right?

I'm still not understanding how water can magically run uphill through the exhaust elbow...? I can definitely see how it could be sucked through in a reverse rotation scenario.

I'm all for alternate ideas but they have to make logical sense.

 

[SKYCHENEY]

Water getting by the water pump would put the water in the oil right?

So, where did all the smoke come from?

I'm still not understanding how water can magically run uphill through the exhaust elbow...?

I'm all for alternate ideas but they have to make logical sense.

And there's the mystery. Smoke could be from running backwards. And if it did, I would suspect it would smell of unburned fuel as it isn't gonna run right in reverse.

 

[cww]

Water getting by the water pump would put the water in the oil right?

So, where did all the smoke come from?

If I'm just hydrolocked (and bent rods) why is the engine still seized now that we have the heads off? A hydrolocked engine should have spun free as soon as I got the injectors out right?

I'm still not understanding how water can magically run uphill through the exhaust elbow...? I can definitely see how it could be sucked through in a reverse rotation scenario.

I'm all for alternate ideas but they have to make logical sense.

The most likely scenario is probably that water got in from backflow up the exhaust rather than slipping by the pump. I don't know why you are of the mind this is impossible, sure it is not supposed to happen, but it does. It wouldn't put water in the oil, it would fill up the cylinders that are closest to the exhaust with water. Water being uncompressible it would hydrolock and bend the rods on those cylinders when you tried to start it. I can tell you from firsthand knowledge that it acts and sounds exactly how you've described. I ruined the generator in my sea ray this way.

I had the marina replace some through hulls and they used a scoop intake on the genny which is a no-no. The next time we had the boat out it was a cool day and we were running with the gen off until it was time to make lunch. When I went to start it I got a loud metallic *CLUNK* followed by a bunch of starter noise and the engine acting like it was seized. I had to get it rebuilt because the rods were bent. That was a bad day.

As to why the engine still isn't turning over now that the cylinders are dry, rods don't un-bend themselves.

 

[rsmith]

I don’t have time to look it up but from what I remember the low rpm wasn’t just a low oil pressure issue is was to do with the oil control ring not distributing the oil on the cylinder walls properly and causing excessive wear and scoring. Don’t be stuck on this run backwards idea that you don’t find the real problem and this happens again. I would think if what you say is true your engine room would look like the inside of a coal mine.

 

[racclarkson@gmail.com]

It wouldn't put water in the oil, what it would do is fill up the cylinders that are closest to the exhaust with water. Water being uncompressible it would hydrolock and bend the rods on those cylinders when you tried to start it. I can tell you from firsthand knowledge that it acts and sounds exactly how you've described. I ruined the generator in my sea ray this way.

I had the marina replace some through hulls and they used a scoop intake on the genny which is a no-no. The next time we had the boat out it was a cool day and we were running with the gen off until it was time to make lunch. When I went to start it I got a loud metallic *CLUNK* followed by a bunch of starter noise and the engine acting like it was seized. I had to get it rebuilt because the rods were bent. That was a bad day.

Raw water getting past a pump and into the motor is not possible on these boats. Unlike a Mercruiser set-up, for example, the raw water cooling loop is a closed loop. Raw water can only enter from backing down hard with water reversing up the exhaust and into the motor via the turbo. Rusty wasn't backing.

In the generator case, water being forced in on a stopped generator would first fill up the water muffler and then back up, as you said. I would not leave a generator seacock open underway w/o the genny running. In reality, a positive displacement pump in good shape will not let water past. Regardless, those are two different systems.

 

[JuiceClark]

....and fresh saltwater in the turbos.

That's a head scratcher.

 

[rsmith]

....and fresh saltwater in the turbos.

That's a head scratcher.

Is their a different between fresh salt and stale salt?

 

[rustybucket]

The most likely scenario is probably that water got in from backflow up the exhaust rather than slipping by the pump. I don't know why you are of the mind this is impossible, sure it is not supposed to happen, but it does. It wouldn't put water in the oil, it would fill up the cylinders that are closest to the exhaust with water. Water being uncompressible it would hydrolock and bend the rods on those cylinders when you tried to start it. I can tell you from firsthand knowledge that it acts and sounds exactly how you've described. I ruined the generator in my sea ray this way.

I had the marina replace some through hulls and they used a scoop intake on the genny which is a no-no. The next time we had the boat out it was a cool day and we were running with the gen off until it was time to make lunch. When I went to start it I got a loud metallic *CLUNK* followed by a bunch of starter noise and the engine acting like it was seized. I had to get it rebuilt because the rods were bent. That was a bad day.

As to why the engine still isn't turning over now that the cylinders are dry, rods don't un-bend themselves.

A generator uses a lift exhaust system. Which will indeed flood an engine as you have described. My 8v92's use a shower injection on the down slope of the exhaust, which will not flood the engine with saltwater under normal operating circumstances (even if actively pumping water through the engine)

 

[rustybucket]

Is their a different between fresh salt and stale salt?

It was so fresh it still had flying fish swimming in it! Think I saw a baby triple tail as well.

By 'fresh' I was inferring that it had not been through a cylinder or engine, it was crystal clear and clean.

 

[madhatter1]

Is their a different between fresh salt and stale salt?

There certainly is when I clean the AC strainer that's been sitting for a couple weeks without running AC's for a bit first. STANK!!

 

[cww]

A generator uses a lift exhaust system. Which will indeed flood an engine as you have described. My 8v92's use a shower injection on the down slope of the exhaust, which will not flood the engine with saltwater under normal operating circumstances (even if actively pumping water through the engine)

That was 1 of 2 possibilities I mentioned, the other one being that water may have backed up the exhaust due to wave action on the stern. From your description you were slow trolling with that engine shut down, there would have been no positive pressure to stop that from happening. I understand how a showerhead works, my boat has the same exhaust setup, but that's dependent on the water having somewhere to go. If the exhaust is full of water the only place left to go is into the engine.

This is not some unheard-of freak occurrence, it's a known problem. From your description it certainly sounds like it was hydrolocked. Your subsequent posts today add additional details that you found saltwater up at the turbos, which further confirms my suspicion.

 

[Bernd1972]

Fresh salt water in the turbos might tell a story of a blown intercooler (which could also drown one or two cylinders)

 

[Cricket]

Rusty, after all of the "cause of failure analysis" on the board I have a simple question.
Why not just leave 1 engine out of gear running??

If I remember correctly there's no way to add a trolling valve to an Allison gear?

 

[rsmith]

Rusty, after all of the "cause of failure analysis" on the board I have a simple question.
Why not just leave 1 engine out of gear running??

If I remember correctly there's no way to add a trolling valve to an Allison gear?

If there was I would have done it years ago. I’m sure he has the same MH gears as me.

 

[rustybucket]

Rusty, after all of the "cause of failure analysis" on the board I have a simple question.
Why not just leave 1 engine out of gear running??

If I remember correctly there's no way to add a trolling valve to an Allison gear?

Yup, no trolling valve available for allison mh20's unfortunately or it would have been done long ago. I can leave one running out of gear not problem, but I've been told sooooo many times over the years that idling a detroit is the worst thing you can do to them (aside from idling them in reverse rotation lol).