Runaway diesel?

Any one ever have a diesel engine run away on them? Did you find a way to shut it down, or did it run its course?

We once had a small horizontal engine in one of our sailboats that ran away a couple times. The only way to stop it was to block the air intake, the problem turned out to be the fuel supply. The installation of an electric fuel pump cured it, seems when it wasn't getting enough fuel.

7tiger7 wrote:
Any one ever have a diesel engine run away on them? Did you find a way to shut it down, or did it run its course?

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*No, but... I do know that the next thing you need to do is cut off the air supply. Rip off the air cleaner and shove a rag in it. That is, assuming the engine shutoff didn't work.

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Don't put a rag to it if it's turbo'd, better a plywood (or any rigid flat material) cap that will choke off the air without drawing it in.

Positive air shut-offs are available for most diesel engines for a couple of hundred bucks. It would save your engine (and boat) if you had a propane leak while underway if it was to get into your engine compartment. They're also a good anti-theft device. I wouldn't recommend a rag.

Nothing light! I worked at a dealership in the 80's and saw a runaway truck engine suck in a phonebook!

My 1980 VW rabbit diesel would runaway often but only with the pedal down on the expressway. And trust me the added power was a good thing!

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I had a runaway starter once. I was sailing offshore on a very quiet day just trying to keep the sails filled. Suddenly the starter powered up and kept grinding. I fiddled around trying to figure out what was going on and finally stopped it by turning off the main selector switch. It turned out that I had a slight coolant leak that slowly built up a streak of corrosion products that bridged across the terminals for the starter solenoid.

The fuel injection pump is the greatest cause of run away engine's. Check that out before the engine "daylights", or throws a piston through the block. I saw a Cat 3306 daylight at 4200rpm. Messy and extremely destructive.

The older Detroits had an emergency flapper that cut off the air. Remember the little remotely mounted pull gizmos? They had to be manually re cocked in the engine room.

I have oftern worried about a runaway engine. On mine, there is a solenoid that shuts off the fuel supply. That's not what would be called a "fail safe" system.

In theory, the fuel supply can be shut off manually but I haven't been able to identify the rod or lever I would need to push and it's on the side of the engine away from the hatch opening so I would have to climb around a rotating belt and pulleys. Not really a safe option.

My plan is to remove the air cleaner and block the opening but I don't really have a plan of what to block it with. I suppose a piece of plywood with a handle should be made and kept nearby.

rwidman, I know your plan is sincere. Now add the chaos of your engine turning 5000+RPMs screaming in the engine room. Do you think you are going to have the fortitude and concentration to remove the air cleaner and block it with something.....not to mention the hazard of the engine coming apart.

Also, fuel is not always the fuel source in a runaway situation. If the engine can somehow gets it's mouth on some crank case oil, that will do the trick also....or like someone else said, propane. Diesel engines LOVE propane. Propane is to diesel engines what nitrous oxide is to gasoline engines.
My wife's company's main clientele is sportfishermen. Detroit Diesel had just repowered(or rebuilt) one of their clients boats(12V) and her boss was one of the unfortunate ones to be on board for the sea trial. One of the engines ran away due to an improperly installed injection pump. There are not many things that are gonna stop a V12 engine from it's hunger for air while turning xxxxRPMs. The engine came apart. Luckily, no one was hurt and the structure of the boat was not harmed. The Detroit people held up there end of the bargain by taking care of all of the damage and clean up. He said the engine room was black and dripping with oil. To say he was frazzled when he got back to the office is an understatement.

I bought a boat from a guy that had a small Hunter Sailboat with a one cylinder Yanmar in it. There was a low clearance bridge between his house and the bay(Bay St. Louis, Ms.). He said he was able to "Tip" his boat(ie heal it over) and get a few more inches/feet of clearance. One time the tide was a little higher so he got his whole crew on the rail and was clearing the bridge. Well the crankcase oil somehow made it into the combustion chamber due to the tilting of the engine and it ran away. In his case, a rag would work and it did.

PS...there are "tipping services" along the Okiechobee Waterway for those pesky 5xft bridges...

The 671 almost was a run a way.* The seal between the fuel pump and the oil pan/sump failed so diesel was being pump straight into the oil pan.* If the diesel/oil mixture got high enough the engine would have run away.* Lucky, I check the oil every time I start it and noticed the oil level as about 1 to 2 inch higher than it should be?* The cause was the new low and ultra low sulfur diesel does damage older seals.* When we pump out the oil there was 7 gallons instead the not normal 5 gallons.*
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The only good news is the diesel oil mixture clearned all the gunk out of the 671.* So if you have an older engines make sure you check the oil level for low and*HIGH levels.*

As I understand it the problem on the 2-strokes is that some particular combination of events can lead the engine to run off its own oil sump.* I've never paid enough attention to the problem to understand it fully but the concept is that the engine draws air through the crankcase and picks up enough oil in the process to sustain combustion.* That's why Detroit incorporated the shutdown flapper but it doesn't exist on all 2-strokes.* My 8-92TA in my bus for example doesn't have one and I don't understand why not - perhaps because it is turboed.* I've never paid close enough attention to see whether that is the difference but I know from hard experience that a Detroit with the flapper tripped will either not start at all or will run like **** once it does start.

What about a wood plug, cut / shaped to fit into air intake for a tight fit? I have a turbo, and would think the turbo impeller would just shred the rag once it got sucked in.
Oh and I heard that if the engine sucks in halon, it will not shut it down, but will only combust the halon, and produce toxic exhaust...

Haven't had a runaway, but a friend had a Yanmar 3GM in his yacht and, after partying too hard one night, (loud stereo = dead batteries) had to hand-crank it in the morning. It kicked back and fired up running backwards!

Blowing the exhaust through the air filter quickly filled the boat with fumes -* we all thought it was funny as a fight!

Engines will combust halon, and the reason most of the new boats have an automatic shut down if the halon goes off.* Our insurance required we install an automatic shut down on the gen set as boaters tend to leave the running while away from the boat. **

Funny as a fight. Now that is a new one on me.

Can I use that.

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SD

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You're welcome - maybe it's antipodean.....

Are you refering to the land mass *or the artists?

SD*

Us guys down here who stop the world getting top-heavy...

*"automatic shut down on the gen set as boaters tend to leave the running while away from the boat.**"

That happened*4 years ago to a sailboat on a town mooring at Block Island*and the boat caught fire after the engine overheated and kept on running. At the MTOA rendezvous we had at Mystic Seaport the next summer we saw the video that the towboat operator had taken using his boat cam. Luckily they were able to release the boat who was rafted and only the sialboat burned. No major injuries,no loss of life thank goodness. No environmental mess. Just one burned out hull and a tow job back to themainland.



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Yeah, I did have a 671 (238) run away in an old crackerbox GMC sleeper tractor. I was on the phone about 200 ft. away when the prospective buyer cranked it up. It sounded like a swarm of bees till it came out the bottom. The buyer still took it to restore with a spare engine I already had sitting in the yard for it. The original engine hadn't been started in a year or more, and was really worn out.

When an engine is so crapped out that the rings pass enough lube oil for the engine to run on runaway is possible.

Runaway two-stroker

What do you mean fuel supply?* Too much fuel pressure, or the control unit wasn't properly controlling the fuel dilivery?* Had my Ford Lehman 120 run away this past weekend and am not sure why!

Yes, I did once and like everyone else, I shut her down by cutting off the air. The reason she took off was that a seal on the lift pump went bad and let diesel fuel leak into the engine.

r-rossow wrote:
Runaway two-stroker

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What a bunch of morons!!* I can't believe they would start that thing without having it secured to the ground.* They're lucky it didn't jump off that base and pin one of them or blow up in their face?
I guess that is why they always have an ample supply of Darwin Award candidates?* Gene pool cleansing at its best!!

"Engines will combust halon, and the reason most of the new boats have an automatic shut down if the halon goes off."

Not really , the volume of Halon is very limited and the shut down is to keep the engine from working as an air pump, and pushing all the Halon overboard.

Edelweiss wrote:r-rossow wrote:
Runaway two-stroker

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What a bunch of morons!!* I can't believe they would start that thing without having it secured to the ground.* They're lucky it didn't jump off that base and pin one of them or blow up in their face?
I guess that is why they always have an ample supply of Darwin Award candidates?* Gene pool cleansing at its best!!

Morons is right.* Yet they post the video themselves as if they are proud of what they did.* If they don't kill themselves, someone will die immitating them.

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