I Said "STOP!" Already...!!!

[markpj23]

Finished all my cold checks, changed the oil, cleaned fuel filters. All set to fire her up again after several months (ashamed to say ....)

Cranked up just fine. Air lock in the sea strainer - no problem, just burp it and all is well. Strange that the tachometer on the control panel went up to about 1000 rpm then dropped to zero. Hmm... no panel lights either.

OK let's shut her down and check that out. YOIKS - the big red STOP button does nothing! Check the panel fuse - all is OK there. No gage readings at all. Engine still idling happily..

So flashbacks to a day when I witnessed a 6-71 runaway and self-destruct back in my Navy days. Why do those things always come back to you at the worst possible time?

Long story short - I found a splice in the main power feed to the engine panel. And of course the splice had come apart. Fixed that and the red Stop button works again! Phew!!

So exactly how would I have shut down otherwise? Yanmar "C" type panel and 4JH2-DTE. I'd hate to have to pull the fuel line and then bleed the injectors afterwards. Going to dig through the manuals on this one...

[marty9876]

Hit something harder than the boat?

I read someplace to take something other than your hand, and solid, and cut off the air intake to stop a run away diesel engine.

[Just one Fish]

I know absolutly nothing about deisels but im assuming that they have no spark plugs and coil so you couldnt just pull the coil wire huh...

[Vasco]

Just saw a cruiser have a bad accident because his electric stop worked when it shouldn't have. Killed the engine in strong current as he was trying to pick up a mooring buoy. Guess the stop shorted and killed the engine. His wife got hurt real bad trying to help. Had to fly to Nassau for medical attention. My 4JH3E has a mechanical stop.

[By Invitation]

Your "engine stop" should be a mechanical linkage on your engine somewhere whichs shuts the fuel off. This is usually either a cable or electric solonoid which moves this lever. You should locate the lever on your engine so that in the future you can always shut it down manually by just moving it by hand. 99% chance it is located on your injector pump. If you can't find it you can always stop the air intake with some object - never use your hand! Use a solid object, soft rags tend to get sucked into the intake manifold and you won't like that.

I have stopped a small diesel (genset) by stopping up the exhaust pipe. Larger engines certainly would put out more gas, but not at higher pressure so it should work if you can reach it.

[hellosailor]

Mark-
"So exactly how would I have shut down otherwise? "
There should be a fuel shut-off valve, a small petcock, right where the fuel line exits the fuel tank. Assuming you can crawl down to it, physically shutting off the fuel might do it.

I say "might" because I'm told that if you have weak rings, a diesel can suck oil right past them and keep on running without fuel.

Or you can block off the air intake--again, if you can reach it--but make Real Damn Sure to use something like a cutting board or scrap lumber, because a convenient cushion or hand can get ingested by a strong engine. (Think of those airplane disaster movies where someone is always getting sucked out the window.)

Also in theory, if you discharge a CO2 extinguisher directly into the air intake, you'll displace the air and stop the combustion, but that's gonna cost you at least $25 for a refill. The other two you can practice for free.<G>

[marty9876]

I had forgotten about the weak ring condition- that's just crazy having an engine use it's own oil as fuel. So strange going from have some knowledge of gasoline engines to all this smelly diesel stuff!

[AnchorageGuy]

The electric solenoid on the shut off can be worked manually and that should be your source to shut down the engine. Cut off the fuel as a last resort at the fuel cut off valve. If you don't have one install it. It can be very dangerous and very unhealthy to your engine to try and shut it down by clogging the air intake or anything else. Just don't do it.

[Kanani]

This is a very good thread and some good basic info for most people that are unfamiliar with the operation of their diesel engine.

One of the basics of owning a boat with a diesel engine is to know where the lever is, on the injector pump, that shuts off the fuel. It would be a good exercise for everyone that doesn't have a good working knowledge of the fuel shut-off, to open up their engine compartment and find the injector pump. That will be the big metal thing on the side of the engine that has as many pipes coming out of it as the engine has cylinders. Go to your counsel and push (or in some cases pull) the fuel shut-off and watch what lever moves on the injector pump as your engine shuts down.

After doing this exercise, start the engine again, then manually shut the engine down by moving that lever by hand. It the lever is cable actuated, you may have to pull a cotter pin (or some other fastener) to release the cable so that you can move the lever. I would recommend doing that so that you are familiar with the procedure.

Here is worse case scenario.......there's a short in the engine room that has disabled the shut-off solenoid and the engine room is either full of smoke or on fire and the engine is running......can you shut the engine down while holding your breath and maybe your eyes closed. Unrealistic?????? ....Nope....it is more common than you may think. It happened to me once.

[Kanani]

Originally Posted by hellosailor

Mark-
"So exactly how would I have shut down otherwise? "
There should be a fuel shut-off valve, a small petcock, right where the fuel line exits the fuel tank. Assuming you can crawl down to it, physically shutting off the fuel might do it.

I say "might" because I'm told that if you have weak rings, a diesel can suck oil right past them and keep on running without fuel.

Or you can block off the air intake--again, if you can reach it--but make Real Damn Sure to use something like a cutting board or scrap lumber, because a convenient cushion or hand can get ingested by a strong engine. (Think of those airplane disaster movies where someone is always getting sucked out the window.)

Also in theory, if you discharge a CO2 extinguisher directly into the air intake, you'll displace the air and stop the combustion, but that's gonna cost you at least $25 for a refill. The other two you can practice for free.<G>

Sorry....that makes no sense........if that were the case, the engine would keep running under normal engine shut-down. After-all, your normal shut-down is simply starving the engine of fuel. Not only that, the engine would be putting out huge volumes of smoke while running. If that were the case, when the engine is starved of clean fuel the engine would not have enough compression to ignite engine oil. I suppose, under some freak, overheating scenario, it could be theoretically possible but not likely to happen in real life.

As for the fire ext scenario.....a Halon ext might and does work. Halon works by displacing oxygen. That's why it has been discontinued. If you set-ff a Halon fire ext in a boat, you can actually die from asphyxiation.

[Beausoleil]

We had an unnerving experience last year with the brand-spanking new, not-even-broken-in Westerbeke 120-T4A in Beausoleil. Went to shut down the engine on our way back from a cruise in Maine, and she just kept on running.

I pulled up the floor boards in the salon and took a look at the engine. The engine-stop solenoid was just hanging by its plunger, just swinging in the breeze. The steel bracket that mounts it to the engine was snapped in half...

[Morgan Paul]

I like my Atomic Four Gasoline engine more now that you guys scared me out of repowering with a Diesel.

[Alan Wheeler]

Some good comment here. Kanani is right, get a good look around your engine an identify what is what.
Although in emergencies you can shut down engines by stopping thenair intake or shutting off fuel, they are not good for the engine and should be left last resort remedies only.
The electrical shut off is only a solinoid attached to the manual stop lever. Find it and remember it. Quickest and safest way to shut down. Turning off the fue has too issues. It ca take awhile to run the fuel out enough to starve. As it starve, then engine can lean out. You will notice sometimes an engine will give a very short rise in RPM just before it dies, due to fuel starvation. That is the engine leaning out and it is not good for it.
Starving the engine o air is the exact opposite. The injectors are happily squirting fuel in to the cylinder. As the revs die, the rack opens and squirts even more in, flooding the cylinder.
A runaway engine is due to oil getting in via the air intake, not past the rings. This can happen if exccessive blow-bye acurrs and oil builds up volume in the upper head region and then over comes the breather and gets sucked in the air intake becoming fuel.

[markpj23]

Originally Posted by Kanani

...One of the basics of owning a boat with a diesel engine is to know where the lever is....

Having just gone through this I couldn't agree more. I was lucky this time as there was no urgency, but I realized right away that I should know how to do this in my sleep.

I almost didn't post this thread as I thought it might be no big deal for the forum. Turns out it was probably worthwhile.

Like I tell the Admiral (too often I confess), if nothing else I can always serve as a bad example