Running Diesel tank empty?

[rbk]

Originally Posted by Compass790

Do you know how the manufactures enable you to stop a diesel engine?
I'll let you know as many haven't thought it through.
Diesel engines have a mechanism to SHUT OFF THE FUEL SUPPLY
Therefore they must run "dry" every time you stop them.

Good warning earlier about turbos but OP's engine is non-turbo

Hope if I'm flying into the bush & the pilot runs one tank dry he warns me tho as it might get rather smelly in the cabin otherwise.

No. They restrict fuel flow so the pump runs into a vacuum but there is still fuel in the pump. Same happens when you shut the supply off at the tank. There’s still fuel in all the lines all the way to the injectors just not enough pressure to continue the flow. You can open the shut off and start the engine without bleeding although it may take an extra turn to build the pressure.

[Compass790]

Originally Posted by rbk

No. They restrict fuel flow so the pump runs into a vacuum but there is still fuel in the pump. Same happens when you shut the supply off at the tank. There’s still fuel in all the lines all the way to the injectors just not enough pressure to continue the flow. You can open the shut off and start the engine without bleeding although it may take an extra turn to build the pressure.

Yes I grant you it's a little different but I'd argue not enough to matter. If you read the OP's post carefully he has a self bleeding engine. Just let the electric pump prime it for a minute, he says, then it starts.
If you have to start cracking injector lines etc it's not worth it.
But he doesn't so I can't see the problem with what he wants to do apart from being a PITA refuelling @ sea.

[rbk]

[QUOTE=Compass790;2955639]Yes I grant you it's a little different but I'd argue not enough to matter. If you read the OP's post carefully he has a self bleeding engine. Just let the electric pump prime it for a minute, he says, then it starts.
If you have to start cracking injector lines etc it's not worth it.
But he doesn't so I can't see the problem with what he wants to do apart from being a PITA refuelling @ sea.[/ QUOTE]

Even with the electric pump it cannot push fuel into the injection pump. All moving parts in the IP will be free of lubrication for the last few seconds of running and the time it takes to run fuel through the IP to the HP lines. Again I didn’t say it will cause immediate catastrophic failure of the IP but it’s like running your raw water impeller dry, it will drastically shorten its life span; but sometimes it happens or is required but should best be avoided.

[Compass790]

Even with the electric pump it cannot push fuel into the injection pump. All moving parts in the IP will be free of lubrication for the last few seconds of running and the time it takes to run fuel through the IP to the HP lines. Again I didn’t say it will cause immediate catastrophic failure of the IP but it’s like running your raw water impeller dry, it will drastically shorten its life span; but sometimes it happens or is required but should best be avoided.[/QUOTE]

Well we'll have to agree to differ then. I've never seen a diesel film disappear in a few seconds & I've never seen self bleeding diesels with manufacturer warnings about running out of fuel. But hey the O.P. can decide who made the better case. I'm ok with whatever he decides.
I'm never going to fear for my injection pump life by running out of fuel. Dirt & water is a different story. But I could be wrong !You haven't convinced me that I am though.

[Alita49DS]

[QUOTE=Ecos;2955140]

Originally Posted by Alita49DS

Err, sorry. I thought this was a site about boats. Which tend to have diesel engines. Not something I am aware are fitted to planes.




Why did you feel the need to comment on something you know nothing about?
There have been diesels in planes since WWII.

Apart from planes being a total irrelevancy here, what you write prompted me to check how exactly how irrelevant diesels in planes are. From Wikipedia:

"The aircraft diesel engine or aero diesel has not been widely used as an aircraft engine. Diesel engines were used in airships and were tried in aircraft in the late 1920s and 1930s, but never widely used."

There is apparently some revival in interest but clearly it is you who might want to do some background reading.

I repeat, in my view planes are of no relevance here. Affording a boat is hard enough!

[Raggedglory]

Originally Posted by 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 ;-)

I took the inspection plate off of my tank after draining most of the diesel and i could see a darker colour but nothing distinct. I took a cheap wet vaccuum with a long rigid hose and vaccuumed it dry. I then poured clean diesel all over the tank sides and revaccuumed.
I now am secure i have a very clean tank.
There was a lot of dirty stuff and water below the drain tube level upon inspection after dumping out the vaccuum contents.
Messy job though. I had water in my tank from a bad O ring and wanted to be sure i had it all out.
This action was suggested to me by a good diesel mechanic as an inexpensive d.i.y. way to save money and get the job done.

[txg]

I'm sorry for not coming back to this thread earlier, but we've been out sailing. We did our last long leg that exceeded our range under power (Azores to Spain) and did not run out of fuel, so the question of this topic is not that important for me anymore.



Still, it is kind of sad that most of the many answers in this thread are just completely useless. Why all this discussion about airplane engines?


Also, i feel like most people did not understand what i was actually talking about. Maybe this is due to a language barrier as i'm not a native english speaker, but so far it has never been a problem for our many American friends to understand me.



Anyways, this exactly sums up what i have been talking about:

Originally Posted by sailingharry

I read it this way. He's out on a passage. He's used 80-90% of his fuel, but would like to continue motoring (still probably has 5 or 10 hours left in the tank). He'd like to KNOW he's got 10 hours in reserve. So, he wants to motor until he runs out, then put in the 20L and then consider himself on "emergency rations." He could put it in earlier, but then he'd miss out on those last 5 or 10 hours of motoring. And, when making landfall, if his tank is low, he can add the 20L when still 10 miles offshore. I think I like the idea.

Some things i would like to add:


-Our tank is clean, so crud is not a problem. This is not a guess but i KNOW it is clean. I open it up regularly (about twice per year) and inspect it.



-At least for our way of motoring, it is NOT true that fuel consumption is always the same. I've written down engine hours at each refill for over 1000 hours of runtime now and the consumption per hour differs a lot depending on use. The range so far is 1.4L/h to 2.7L/h. These extreme numbers are on the one hand from a lot of charging at anchor and on the other hand from fast bashing into headwinds. Still, when taking these extremes out of the equation the range is between 1.7L/h to 2.3L/h for "normal" motoring which is still a considerable difference. We have a 120L diesel tank which equates to 52 hours of motoring at 2.3L/h, while it would be 70 at 1.7L/h. That is a BIG difference or nearly another 100nm of motoring. We carry another 160L in jerry cans which increases these numbers even more.



-Regarding safety: I'm talking about being out at sea (like seriously off shore) in light winds and flat seas. When being this far out, we would never navigate so close to a big ship that a refueling break of one minute would be an issue.



-Regarding refilling at sea: That's easy without spilling a single drop. We have our jerrycans on the sidedecks and near the mast base, strapped down with ratchet straps. When on passage, we use a long siphon hose to transfer fuel to the internal tank without even bringing the jerry cans to the cockpit. Works perfectly fine.





Regarding the other issues brought up in this thread: I don't think that the injection pump will die faster when run dry maybe once or twice per year.

What i'm not sure about is the injector bleeding issue, i get the point that this may be a problem that can't be solved by our electric pump.

[az_r2d1]

Originally Posted by wingssail

In certain jurisdictions fuel was colored to indicate where it was purchased and whether tax was paid on it. Diesel purchased for road use was taxed at a lower rate and was not legal of use in vessels. Authorities could check the color of your fuel to see if it was legal or not. Penalties could be severe.

wrong. other way around.

[az_r2d1]

Originally Posted by Pete17C

At the end of the season, and many times after every use, lots of folks run an outboard (boat engine) dry. Gensets too.

And it's SOP every time you shut down a piston aircraft engine.

Sometimes it makes sense.

Outboards don't use diesel but gasoline. diesel lubricates, gasoline does not (well not like diesel).

I bet the airplanes that run them empty don't have high pressure diesel pumps and injectors. It's a sure way to ruin them if you do this every time.

[az_r2d1]

Originally Posted by sailingharry

Close, but backwards. Road tax is expensive, and off-road fuel is (in theory) cheaper because it isn't taxed (but the revenuer doesn't care which is cheaper -- he cares if the road tax was paid). So, the red dye is for un-taxed fuel. Put it in your tractor or boat all day long, no worries. But put 10 gallons in your car or tractor trailer (more likely to be caught on the commercial trucks -- no one has ever inspected the fuel in my diesel car!), and it will show traces of red for the next two or three tanks.


Now, practically, I can buy off road diesel (no tax, red dye) at the fuel dock or at a High's gas station -- but it is almost always cheaper to buy regular diesel (road tax included) at Wawa.


It is also going to be fresher (the Wawa pumps a LOT of fuel!) and is easier than going to the fuel dock. And the Wawa never bitches about my small fuel purchase either!

Find an area with some agriculture. Around me the dyed diesel is used a lot for tractors. Saves 30 cents a gallon. Diesel doesn't need to be fresh. It needs to be dry and stored correctly. Diesel with no water in it can be stored for a loooooooong time.

[az_r2d1]

Originally Posted by Jlp0217

Wow, some of you are very paranoid. He didn't say that he would routinely run the boat out of fuel. Only if he ended up on emergency reserves. He didn't say what his capacities are, but for example, assume he has a 30 gallon tank, and 6 5 gallon gerry cans. He adds 5 of the Gerry cans as he's running as many have suggested, but keeps the last in reserve. After running the engine for 100 hours on his passage, he should have burned 50 gallons at average rate, but if off by only 10% he could now be running on fumes or still have 10 gallons left.
My engine burns 0.5 gph at idle, and 5.6 gph at full throttle, thats a 1020% range. So, personally I like the idea of running the tank dry to know that I have 5 gallons left, assuming the weather and sea state is such that running dry would not create an emergency situation.
As far running the tank dry harming the engine, I cannot believe that is a serious consideration. No measurable wear is going to occur in the few seconds it takes for the engine to stop spinning. If its turbocharged and requires a cool down period that is a different matter.
As far as running the tank dry gathering gunk that would not otherwise get sucked up, I don't believe that happens, I think gunk get sucked up when fuel get low but still enough to slosh around in the tank. Ether way getting the gunk out of the tank and into the filter is a good thing.. If your tank is dirty enough to clog a filter, the prudent thing to do is get it cleaned, not avoid using all the fuel.

Having your engine run dry is just plain stupid. It means you have no clue what you're doing running on engine. Pretty good chance it will happen to him at that critical moment when entering a port in big breakers.

Best to stay off a boat I say.

[az_r2d1]

Originally Posted by tdgaffney

To Sailing Harry - Thank you for the 'correction' on gas taxes. I called the Washington State Revenue department and they didn't know the answer re taxes (?). The fellow was nice enough and said he'd look into it and call me back, but he hasn't, not yet.


The other question I had posed was "will automotive diesel be Harmful to my 3YM20?" Of course, I am SURE the answer is NO, diesel is diesel. But as Mark Twain said "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't right!"




So: Will automotive diesel be harmful you my 3YM20? (sign me Nervous in Seattle)

nope, it's perfectly fine.

[Alita49DS]

I agree with just about everything that Cruisers & Sailing Forums - View Profile: txg, as the person who posed the original question has said.

Especially when he writes "Still, it is kind of sad that most of the many answers in this thread are just completely useless. Why all this discussion about airplane engines?"

He has nothing to apologise for in stating "Maybe this is due to a language barrier as I'm not a native English speaker, but so far it has never been a problem for our many American friends to understand me. " The people who need to apologise are those people here who became deeply offensive, in at least one case abusive, when it was pointed out that discussion of airplane engines was way off topic. The question was perfectly clear. Not something that can be said for a surprising number of the answers.

[tdgaffney]

My Washington State Revenue department guy just now called me back (restores my faith in government (?).


He said that the state tax is only imposed on automobiles as a road use tax and so the dye is added to show that this fuel has been so taxed. Using this fuel in a boat is not a state taxing problem Actually, he said, as this tax does not apply to farm vehicles or boats one can actually submit receipts for such fuel to the state taxing authority and request a refund for state road taxes paid.

[Compass790]

Regarding refilling at sea: That's easy without spilling a single drop. We have our jerrycans on the sidedecks and near the mast base, strapped down with ratchet straps. When on passage, we use a long siphon hose to transfer fuel to the internal tank without even bringing the jerry cans to the cockpit. Works perfectly fine.





Regarding the other issues brought up in this thread: I don't think that the injection pump will die faster when run dry maybe once or twice per year.

What i'm not sure about is the injector bleeding issue, i get the point that this may be a problem that can't be solved by our electric pump.[/QUOTE]

I made my comments based on your statement in OP that after you ran out of fuel & had refuelled the electric fuel pump only had to be switched on for a minute & then you could start the engine WITHOUT needing to bleed the injectors?
I assumed you had tried this.
Thats what I read in your OP. If your engine starts & runs fine you have no need to bleed the injectors. You only have to bleed injectors if the engine wont start.

Hey threads drift sometimes, dont have to read the airplane ones if you dont want to. Dont be sad.

Your refuelling method sounds good for an @ sea job. I'd still manage to spill diesel tho