Draining the fuel tank

[kerrye]

While the engine seemed to run fine on the fuel which was in the tank when I purchased my A25, I've decided to drain it. It's at least 8 yrs old. Pumped out a couple of pints and it smells a little varnishy. It was kind of hard to tell since initially the fuel I pumped out was in a plastic water bottle but it looked to have things floating in it which resembled the stuff floating in a bottle of maple syrup I left unrefrigerated too long. Bought a 12 volt diesel transfer pump at the parts store and will pump it into some 5 gallon buckets. Not sure about disposal yet. I'll get a look inside the tank once it's empty. I have an inspection camera which can fit inside the fuel gauge hole.

[kerrye]

Drained the tank today. Fuel looked fine and tank had neither sludge nor water. I think what happened was that when I first pulled a sample last week from the fuel line it looked ok. It was in a clear bottle stored in the cockpit. When I looked at it yesterday it was very cloudy and I saw algae growing in it. I shook it up and it turned opaque and very dark, which I think was a result of the algae breaking into small bits. I'm pretty sure what occurred is that once the fuel was exposed to sunlight, algae grew. There wasn't actually algae in the dark tank. Just to be sure I pulled a sample today and put it on my front porch in the sunlight to see what happens. Pictures attached of the process, fuel I drew out today and a comparison of that fuel with the fuel from last week. Pump cost $50. Wired it up with alligator clips and a switch near the pump. Added one extra inline filter in front of it. Took about 2 hours and 15 minutes to pump out 15 gallons of fuel, Inspected the tank with my inspection camera. I think the fuel was at least 8 yrs old, I'll confirm that with the previous owner. I used 5 gallon buckets to store it since they cost $5 as opposed to $20 for a 5 gallon diesel container. I used Smacksman's system of a PVC pipe to hold the fuel line at the bottom of the tank which is where I got my initial sample today and from where I drained the whole tank.

[sail149]

Do you know anybody with a diesel car or truck? Run it thru a filter and they are good to go!
I used to top off my gas tank with 2 stroke mix in the past and never a problem, just some extra upper cylinder lube!
Gas does not go bad only the additives in it. ( unless it evaporates).
Diesel even less so it's just oil. Bunker fuel for ships is so thick and gooey they have a seperate pre heating system before they feed it into the engines!
What were you going to do with the fuel you took out?

[kerrye]

I've got a number of diesel vehicles. I may just burn it in them. It's hard to find a place to dispose it.

[kerrye]

Update: I've been burning the 8+ yr old fuel in my daughter's 84 Mercedes SD. I've put in about 10 gallons so far mixed in with some existing 4 yr old diesel fuel and no problems. I did dose each 5 gallon bucket of the old fuel with a biocide and diesel preservative. I am finding a layer of black scum on the bottom of each of the 5 gallon buckets. I don't know if this is dead algae or if it is living algae on the bottom of the bucket because the diesel is sitting on top of a microscopic layer of water which supports the algae. It could be living algae because since I've removed the fuel from a stainless tanl and put it in orange Home Depot buckets it has been getting more light which would encourage the growth of algae. It could also be dead algae which the biocide has killed. I do have a sample glass bottle of the fuel sitting on my front porch in the sun. I'm not seeing anything in that particular sample. I'm not pouring the black stuff into the Mercedes.

[Beta Don]

I had that same black sludge which plugged up my Racor 500 filter element after about 200 hours of running. I had also drained the tank of perfectly good looking 12 year old diesel fuel and I *thought* the inside of my empty tank was clean as a whistle - Evidently not, because I filled it with 70 gallons of new fuel a week or so before we left and after burning a little over 200 gallons of fresh fuel, my filter was clogged

My Dad had an in the bed 75 gallon tank he only used when he was pulling his RV. Even though I advised him to treat it with biocide if he wasn't going to use it, he didn't bother. He called me some months later and told me that his 75 gallon tank would only hold 30 gallons or so - Yep, the rest of it was 45 gallons of black 'mud'

Maybe the diesel doesn't go bad, but the algae can sure 'eat' the fuel and what's left afterwards isn't pretty

Don

[JT48348]

No offense I'm no scientist, but I don't think that's "algae " or anything growing. The common perception that algae grows in diesel is in fact the diesel breaking down. While it is possible for microbes to grow in diesel, more likely any sludge or particulate matter is in fact diesel breaking down to component molecules.

There are several research papers on this. Hard to find. But this is a cogent explanation which mimics what I've read on the technical side:

"What is Diesel Fuel "ALGAE"

Algae are a life form found in water, similar to algae growing in an aquarium. However, for years, people have been referring to tank sludge and to the jelly, slime and other contaminants found in fuel filters as "algae". The colloquialism "diesel fuel algae" is widely used and understood. However, there is no relationship between the "algae" growing in your aquarium and the sludge "growing" (forming) in your fuel tank and showing up on your filter elements.
There are three basic areas of concern in fuels and oil. They are: 1. water 2. in-organic debris (sand, dust, rust, etc.) and 3. organic debris (fuel breakdown products and waste products of fuel deterioration and re-polymerization). The organic debris represents more than 90% of all the contaminants found in fuels and oil. It is this organic debris, the sludgy, slimy, acidic material that people refer to as "diesel fuel algae". It could also be called polymer, tar or wax and asphalt!

In South America, people refer to the "Algae" as "mud". In gasoline, the organic fuel breakdown products are often referred to as gum, varnish, or lacquer. Taken literally these words could be confusing too."

From
http://criticalfueltech.com/faq.html



There's tons of mis-information about this on the Internet. But if you search multiple sources and steer towards the more scientific sources you will see that."algae" is a common misconception. Less than 1-5%of contaminants are actual microbial organisms.

[kerrye]

Are you suggesting that biocide is unnecessary? There wasn't black slime in the tank when I emptied it and and there weren't any visible particles in the diesel when I put it in the 5 gallon buckets. So whatever it is, it came to be in the few weeks between the time I removed it from the tank and put it in the buckets. The only difference apart from the container it was in was that I added the suggested doses of biocide and diesel fuel stabilizer. Perhaps those products themselves cause the sludge.

[kerrye]

Ironic that the company in the link above calls its preservative product Algae X. Here's another paragraph from their page:

Contaminant build up resulting from excessive microbial growth and bio-degradation of fuel can cause filter plugging. Micro-organisms, bacteria and enzyme activity, fungus, yeast and mold cause fuel degradation and the formation of waste products. The process is similar to milk turning into cottage cheese, a different form of milk. Of all the microbial debris and waste products in the tank only about .01% is bugs. Even though microbes may cause and accelerate the process of fuel degradation, it should be clear that the waste products clogging your filter are not the microbes but fuel components which have formed solids.

Frequently, the application of a biocide aggravates the situation and turns bio-film into solids, creating a real fuel filter nightmare. Bio film develops through out the entire fuel system. It grows in the water fuel interface and on the walls, baffles, and bottoms of storage tanks. An unlucky end user may be filling up his tank and getting this debris delivered as a part of his fuel, for the same price as the fuel.

[JT48348]

I quoted that piece, because like I said, it best represents the technical papers I've read on the subject in laymans terms. And it was one of the first Google answers to : does algae really grow in diesel? (No)

The fact that the same website sells Algae X or other hokum would be the part I pointed out as : misinformation.

Listen don't take my word for it. Read up on it. Do the relevant homework and make your own choice.

Me personally, micro organisms are a minor issue. My tank has a layer of black gunk in it. I know from science it's not a fungus,bug, slime, mold, micro bacterial carcass or otherwise. It's parafin, asphalt, tar, and other crap. The issue to me is the diesel breaking down and the various contaminants. The notion that you put your bucket of diesel in the sun and micro organisms blossom like mold spores sounds like pseudoscience.

[kerrye]

I don't know what the black slime is. I just know the circumstances in which it came to exist. I also know, as I mentioned in the first post that I saw some strange stuff suspended in the fuel bottle which contained the first pint or so I pumped out and I resembled some stuff in old unrefrigerated maple syrup I once had. It also wasn't there when I first pumped it out but appeared after sitting for about 4 days in the sun. I don't know what either of that stuff was.

[kerrye]

This piece is pretty specific about the variations of organisms that can grow in diesel:

http://www.oillab.co.nz/diesel_bug_explained

BP, which I assume must know something about diesel fuel explains the growth of fungus in diesel fuel:

http://www.bp.com/content/dam/bp-countr ... -boats.pdf

[kerrye]

http://www.sciencedirect.com/science/ar ... 3689900043 The abstract on this article specifically identifies the forms of life growing at the interface of diesel and water.

The life forms appear to be either fungi or mold. Not algae.

[kerrye]

Some quick googling reveals that fungi/mold does grow in maple syrup. The Figure 1 image on this page is what my maple syrup looked like and also what the first diesel I pumped out of my tank (mostly out of the filter actually since I unhooked the hose downstream of the filter to pump it out) looked like, kind of a hazy stringy slimy stuff.

http://www.omafra.gov.on.ca/english/cro ... rt14a2.htm

[JT48348]

Wait wait. You didn't just post a bunch of links that sort of not really have anything to do with topic---AND switch the conversation from diesel fuel to maple syrup?

Lol. Good one.