Diesel engine stop question

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Dieseldame
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Diesel engine stop question

Postby Dieseldame » Sat Apr 26, 2008 7:58 am

Okay, here's a mystery for you guys. An fuel gallery alarm goes off on a ship service generator. You go through the normal procedures to shut down the engine remotely but find that the engine is still running when you arrive on site. You hit the local stop button but it still runs. You try revving the engine and stopping it again...still no luck. You shut down the fuel feed from the Racors and she continues. At this point you are getting excited about the most efficient engine made...what is the problem?

DD

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The Dieselduck
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What type of engine and size

Postby The Dieselduck » Sat Apr 26, 2008 8:19 am

What type of engine and size are we talking about?

Sounds like you should market that thing, ehehehe
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conrod
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Wont stop

Postby conrod » Sat Apr 26, 2008 2:01 pm

The only time I have heard of this was, on med speed, main engine, used for propulsion.

Fuel pumps had been stripped and the wear on the top of the helix was such that there was some leakoff. This means that moving the fuel rack had no effect on the running of the engine..............hence it would run until it ran out of fuel, or exploded at WAY over speed.

Fuel pump gallery alarm ?? Racors ??

If the tip has burnt off on an injector, then you would get a tad too much fuel, which if the engine is fed from a header tank, located AFTER the Racors..............might give a fuel leakage alarm, but not normally in the gallery..................OK, give up, whats the answer ??

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Dieseldame
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The mystery

Postby Dieseldame » Sat Apr 26, 2008 6:11 pm

Engine type is MAK 6M282

The fuel gallery alarm - on this particular engine the pumps are inside the casing behind removable doors. The gallery alarm is designed to let you know when there is a fuel leak as you can't see the pumps unless the doors are off. Interesting design you say...well...there is one born every minute.

Racor. Surprised this is a new term, seems to be everywhere I go. Racor is a brand name that can be used as an add on primary filter or secondary filter. Its designed to remove water and act as a particulate filter (helped with a "bug" problem on another boat), micron size 2 to 30. I would be interested to hear of there are other good options out there for this application.

DD

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conrod
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Racors

Postby conrod » Sat Apr 26, 2008 11:05 pm

I know what Racor filters are, and know all about fuel pump gallery's very common on modern medium speeds particularly from Europe. Bergen, Wartsila, both include two alarms for fuel leakage...........injectors, and pipes within the gallery...............but you still havent told us the answer !!

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JK
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Postby JK » Sun Apr 27, 2008 7:23 am

The fuel leak off line on the engine is tied in with the leak off lines on running engines. Or the leak off line goes back to the day tank under the fuel tank diesel level and is being fed back to the diesel.

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chuck
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Postby chuck » Mon Apr 28, 2008 4:53 am

On the remote stop, does this trip the governor and place the fuel pumps to zero fuel? May want to test this after you find the issue with your fuel problem since it is suppose to be a safety feature of the engine. If this is a Canadian vessel and TCMSB inspector would come on board and test this feature and it did not work, they would not be very happy.
Isolating the Racors did not stop engine. How far away from the engine are the Racor filters? If the engine is only idling, and the fuel filters are located some distance from the engine (one vessel I sailed on had the Racor filters for the generators located in the forward part of the engine room, while the generators were located in the aft), it would take some time for the engine to shut down since you are trying to starve the engine of fuel (pumping the fuel lines dry). Another method you could have used was to starve the engine of air (no air-no combustion). I am unsure if this engine is fitted with an air isolation mechanism. Garbage bags around the air inlets to turbos will work wonders.
If I was on this vessel, I would definitely be searching for the cause of the engine not being able to shut down since this is a safety issue.
Was the engine recently overhauled? I know of one vessel where I work where the fuel pumps were incorrectly overhauled and the engine ended up overspeeding and was unable to shut down until major damage occurred.
That would be my 25 cents worth.

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ArkSeaJumper
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Postby ArkSeaJumper » Mon Apr 28, 2008 7:23 am

Ah, we need more information, was the fuel rack going to zero when the stop was pressed?
When you shut off the fuel at the filters did the fuel oil pressure drop?
I wonder what state the piston rings are in, was it dieseling on the lub oil?
Where you carrying gas? and was there a funny smell around the ER?

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The Dieselduck
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Obviously more than one problem

Postby The Dieselduck » Mon Apr 28, 2008 10:08 am

What a puzzling dilema and a good source of discussion. I hope you will let us know what you did find out. I cannot really imagine anything else that has not been mentioned already.

The suspense is killing us now.
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Dieseldame
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Who would have thought?

Postby Dieseldame » Mon Apr 28, 2008 2:50 pm

I can see that the puzzled look on the shift and Senior engineer's faces at the time of the incident is echoed here in the forum. As much as I love to see gray matter at work and I am sooo tempted to just give another hint. This is what we found.

Chuck, you get points for thinking about the amount of fuel in the lines.

After some head scratching one of the engineers thought to test each of the fuel pumps to see if it was responding to the command from the governor and found one of them was stuck open. A pull and a push and the engine stopped. It had been running off one pump being fed by the fuel in the lines. Further investigation found that the reason for the gallery alarm was a coolant leak in one of the cylinder liners, filling just about everything with a nasty oil emulsion, causing the plunger to rust and stick open.

Did I tell you the one about the 16 cylinder that wouldn't stop?

DD

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JK
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Postby JK » Tue Apr 29, 2008 3:48 am

Did I tell you the one about the 16 cylinder that wouldn't stop


Image

Did it end up looking like this?

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Dieseldame
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Picture worth a thousand words

Postby Dieseldame » Tue Apr 29, 2008 6:50 am

Why yes, JK..I think it looked exactly like that.

DD


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