Running Diesel tank empty?

[Tillsbury]

Not relevant here, but if you have a turbo diesel this is a doubly bad idea -- suddenly stopping the engine after working it hard for a long time can cook your turbocharger.

I've run out of diesel exactly once. I went over the fuel gauge sender thoroughly and got it working properly and calibrated before going anywhere else.

[a64pilot]

Originally Posted by Tillsbury

Not relevant here, but if you have a turbo diesel this is a doubly bad idea -- suddenly stopping the engine after working it hard for a long time can cook your turbocharger.

I've run out of diesel exactly once. I went over the fuel gauge sender thoroughly and got it working properly and calibrated before going anywhere else.

The turbo is a valid point, if you have a turbo and chose to do this, be at low power when it runs out. What happens is that a hot turbo can cook the oil that is left in it, turning it to coke, this coke of course is abrasive and eats out the center section bearing, of course not likely to happen with just one event, but it’s a bad idea to shut down an engine with a hot turbo.

You can of course just run it low on fuel, and then pump out the remaining fuel with a pump. It accomplishes the same thing.

[19thol]

I think it would be a lot easier to just fix the fuel gauge.

[lordgeoff]

Originally Posted by txg

Like most boats we have a rather inaccurate fuel gauge and carry extra fuel in jerry cans. We did several trips >1000nm this year and when it was lighter winds it was kind of hard to plan on our fuel consumption. We know that our fuel consumption averages about 2L/hour, but there are big differences between motorsailing down wind and waves or motoring into a swell without any wind. So we tend to stay on the safe side and stop the engine as soon as we believe we could be down to an emergency reserve.



Our Vetus diesel has a factory-installed electric fuel pump, so bleeding the engine is done by simply switching it on and waiting for a minute while listening to the alarm sound. No hand pumps or bleed screws. The engine is a Mitsubishi S4L, so a standard old-school diesel without fancy common rail or turbocharger stuff.



For the future, i would like to know if there is anything wrong about just using up all the fuel in the tank till the engine stalls and then refill with one last leftover jerry can (20L ~ 50nm range for emergencies and docking).



When i tried to google this problem, only car-related answers came up. There it said that the injectors can be damaged and fuel filters clogged when the tank is run empty completely because of debris in the tank. I know that our tank is absolutely clean as it gets a regular inspection and we used a lot of fuel this year so far compared to the size of the tank. In the last 6 months, the engine ran for 330 hours which equals to about 5.5 full tanks used.



Is there anything i am missing regarding engine damage? The process of refilling and bleeding the engine would take about a minute on our boat and we are talking about being far offshore on the open ocean, so there are no traffic problems or anything like that.

Would it be better to totally drain your tank when you think you have 15-20Lt left? Add your clean fuel Jerry can then inspect you drained fuel and if ok tip it back into the tank. That is a better way than running the engine dry.

[Cheechako]

Note your engine hours.
Fill the tank.
Fill it often and log the hours and gallons each time.
You now know how much it burns in your normal use.

[Cpt Mark]

Originally Posted by redneckrob

First off, the vast majority of all piston engines on airplanes are gas and this is a discussion about diesels. Second, as someone with several thousand hours of flight time who flew professionally for many years.....are you freaking kidding me! No, its not at all common among safe, professional pilots to run a tank dry. I've done it exactly never, and if i ever do it will because of a major failure on my part! I only hope your flying days are behind you, if they aren't I say with all the good intentions in the world toward your passengers...they should be!

No kidding! Hope he never flies in my airspace.

[Sailor647]

How do we tell how much fuel is in the tank? We look. Being able to see inside is also handy for filling the tanks to prevent any overspill and checking cleanliness.

[sailon46]

I recall in St Martin 5 years ago a big power yacht was towed into the French side marina Fort Louis. The professional crew on a crossing flipped to the second tank which some knucklehead had filled with water and don’t ask me why. They had to remove the toasted Diesel engine out of the boat and put another one in at great expense for the owners. They had run dry the first tank and replacement crew did not know about the water in the second tank.
Ernie on the Mary Jane

[S D Sailor]

Please excuse my ignorance, but is it possible to shine a light into the inspection plate of a fuel tank and see debris or impurities? My tanks have a drain "tap" at the bottom (in a most inconvenient location under two bunk boards) and I've often drained a few cups to check for water. I've never had particles work their way to that drain....so how do I find if I have debris?
Also, I think there are baffles to keep fuel from sloshing (46 gallon tank)....which I'm sure impede debris "travel"....
Sorry if this is hijacking this thread....suggestions are welcome (even sarcastic ;-)

[Lepke]

If you buy clean fuel and use a good fuel stabilizer you can have clean tanks forever. I use a 2 micron filter for 500 hours, about 5000 gallons passing thru. My tanks are big enough to enter, so I know they're clean.
I don't think intentionally allowing air into the system, by running a tank empty, is a good idea for a diesel fuel system. Many years ago I was an A & P mechanic. I don't think I would run an aircraft tank empty in flight.

[Boatyarddog]

Originally Posted by Cheechako

Even if you run until the engine quits your tank is not empty. Pickup tubes don't usually go all the way down. Avoid running dry. Why would you?

Just not a good practice, accomplishes nothing.
If you've got an access to the tank, that's all you need to maintain.
You'll fill with fresh fuel and stabilizer.
If you see debris, and you will.
Just suck it out with a Vaccume pump, and reuse somewhere else.

[grantmc]

Finagle's law of dynamic negatives (also known as Melody's law or Finagle's corollary to Murphy's law) is usually rendered as "Anything that can go wrong, will—at the worst possible moment." In this case running out of fuel.

Plus letting the fuel run out is just really bad boat-person-ship. But deliberately running it dry is inviting bad consequences.

[Qayaq]

Running out of fuel until the engine stops will mean that you will have to bleed off the injector pipes. It wont be as simple as just running the electric fuel pump as that is only going to bleed off the low pressure side of your fuel injection system.
Bleeding injection pipes is not a fun job at sea.

[dennismenace111]

Originally Posted by S/V Illusion

When the fuel runs out, most diesels tend to stop running.

Actually, its when the tanks become full of air..that the engine stops running...

[Squanderbucks]

If your tank takes more than one jerry can of fuel to fill your tank. Why not just put in a can when a little over one cans amount has burned down and pour it in. Then you never ever run out.
Why do you feel the necessity to run a tank till it is empty or nearly so before refilling or topping off?