Diesel fuel sediment: what is this??

[kmcshane]

Has anyone ever seen this kind of sediment in their Racor sediment bowl.
I took it apart, cleaned spotlessly, refilled from the aluminum 45 gallon tank.
No, I haven't yet taken it apart again, nor, as suggested, taken a sample in my fingers and tried to crush or analyze the particles. I'm stumped. Is this algae, or some weird aluminum tank contaminant?
Photo 3: No water this time. I think I've sealed the inlet correctly. After that fiasco, this tank was cleaned spotlessly with a soft cloth just two years ago. The aluminum looked like newly polished metal, no hint of corrosion.
Photo 4: Included a photo of the technique I used to process the fuel into jerry jugs, which I then used in my diesel truck without incident.
This full fuel tank diesel has been aboard for a year, treated with biocide, now this...
(sorry, a couple of these photos don't want to stand upright...)
p.s. quick shout out to moderator "A64pilot" for your helpful advice regarding alternator belt dust, which I followed...still looking at the Balmar serpentine, but the pulleys are in alignment, and I'm changing to a Dayco Top Cog belt.

[thinwater]

What additive do you use, and exactly how do you add it? HAve you drained any water in that period? There are reasons I am asking this very specifically.

[Cheechako]

Strange stuff indeed. Not sure, but would guess it's a growth of something. Is it gritty or slimy? Looks a lot like calcium color, which I've seen in water tanks (gritty) but not in fuel tanks.
I have definitely seen slimy stuff that color, on the top inside surface of aluminum tanks... maybe it's a result of condensation water in there on the aluminum...?
Open your access port and scrape a finger on the top inside surface and see if you come up with a layer of that.

[kmcshane]

Originally Posted by thinwater

What additive do you use, and exactly how do you add it? HAve you drained any water in that period? There are reasons I am asking this very specifically.

I used Killem FFPF, which was recommended at Mack Boring for Yanmar diesel fuel. No (noticeable) water in the fuel filter after sealing the inlet thoroughly.
Yes, I'm sure if there is appreciable water, that's a medium for biological growth. And ideally the Killem should have worked on that.
I'll go out today and give it a good run after being dormant for the Summer here in Florida.
More after that.
Thanks for replying, and I look forward to your thoughts.

[thinwater]

Originally Posted by kmcshane

I used Killem FFPF, which was recommended at Mack Boring for Yanmar diesel fuel. No (noticeable) water in the fuel filter after sealing the inlet thoroughly.
Yes, I'm sure if there is appreciable water, that's a medium for biological growth. And ideally the Killem should have worked on that.
I'll go out today and give it a good run after being dormant for the Summer here in Florida.
More after that.
Thanks for replying, and I look forward to your thoughts.

I was NOT asking whether water adds to growth; we know this. I was asking specifically if there was water in your tank. In fact, there may be none at all. This is very good... and bad.

The reason I asked is that Killem, different from Biobor JF, is water soluble (it is diluted in glycol ether, not naptha). This makes it very effective in the water phase. However, sometimes if it dumped in the tank, in good quantity without agitation, it can crystallize and go right to the bottom, and create deposits much like you see. They will seem vaguely like salt. Several additives can do this. If the solids are more slimy, I suspect water emulsion.

Ironically, if there is even a tiny amount of water in the tank it won't happen, since the additive dissolves quickly in the water.

I suggest pouring a little additive in a jar of diesel and watching watching happens. I could very well be wrong, as the circumstances must be just so. But that is what it looks like.

If so, it is harmless. In the future, add the additive while filling so that it is well mixed. That will prevent the problem. Another option would be switching to Biobor JF.

---

Side note. Different biocides attack different bugs, just as different antibiotics target different bacteria (gram pos vs.neg). There can be a case made for switching additives every year, just as doctors try to vary antibiotics. Biobor JF has different activity from Killem, though both are very good.


This link might help.

http://sail-delmarva.blogspot.com/p/...-biocides.html

[Ponzoa]

Looks like Algae to me. Diesel has more BIO in it since some 5 or 10 years ago so we get more of the crap. I've had it clog my fuel line and leave me with the engine off entering a port.

I'm sure you already know but, just in case or for others;

Choppy water will make it move around the tank as it usually sits at the bottom.

The best is to empty your fuel tank and clean it with petrol/gasoline. If that's not possible or practical, experts in my region consider the best option (although there are other good ones) to treat it to be "Star Brite Diesel Additive" for prevention but if your tank is really bad, use the "Tank Cleaner" version. ENZYME is the key word in the product.

[donradcliffe]

Thank you Thinwater!

I use Biobor, but have seen the granular deposits in Photo #2 clogging diesel fuel systems in other boats (as well as my outboards if I use ethanol blend gasoline).

[thinwater]

Originally Posted by donradcliffe

Thank you Thinwater!

I use Biobor, but have seen the granular deposits in Photo #2 clogging diesel fuel systems in other boats (as well as my outboards if I use ethanol blend gasoline).

With ethanol gas the granules are aluminum corrosion (brass jets in an aluminum body--what would you expect!). Great for clogging jets, will not dissolve in carb cleaner. The solution--other than keeping the gas dry--is a corrosion inhibiting additive.


I've been very happy with Biobor EB (not related to Biobor JF--totally different), but there are a few others. I have not worked on a carb in the 7 years since I started using it (all ethanol gas), and I have a bunch of small engines and outboards. I worked on a LOT of them before that. Most additives don't really stop corrosion.



https://www.practical-sailor.com/iss...n_10855-1.html

[kmcshane]

Thanks Thinwater, and other suggestions:
Here's the photo and video after decanting the diesel from the sediment.
I don't know if it will be obvious, but the "granules" are not hard or crystalline to touch, not like sea salt.
The appearance is deceiving, and they are not slimy either. There is some slime, which may be the mixture of non-condensed granules that are floating in the slime medium.
I will follow your suggestion and try the Killem mixed with both pure diesel, and the slime mixture. See if Killem dissolves cleaning in pure, and possibly reacts to the sediment.

[roland stockham]

I have had something that looks exactly the same after leaving diesel standing in the tank. I assumed it was water from condensation plus algae. depending on you fuel setup you may be best draining the tank, clean everything, scrubs the diesel and put it back. I have not found homicide treatments that continue to work for a year. Generally good over winter but need to be retreated about every 3 months

[NYSail]

Looks nasty...... I never fill my tank unless I am going on long trip. I always use my fuel before putting new in..... not run out but get it below 1/8 tank. For winter hope to have less than an 1/8 tank. That way in my opinion fuel doesn’t sit and become food. I also never add any biocide. Again just my way of doing things that has been effective for over 15 years of sailing with a Diesel engine.
Seems like a cleaning of the tank is in order.....

Good luck
Greg

[thinwater]

I've looked at a lot of diesel, and it could be a lot of things, but I wouldn't be too scared.


If you can test the pH of the water that can be interesting. If is sour (pH <~5) that strongly suggests bugs. The other thing that can be helpful is sumping the bottom of the tank. Sometimes you can reach it with an oil vacuum.

[kmacdonald]

Is it aluminum oxide from tank corrosion?

[NYSail]

Originally Posted by kmacdonald

Is it aluminum oxide from tank corrosion?

Great point...... is tank grounded? You should check wire to make sure it is properly connected at both ends of tank in fact is aluminum.

[GeneM]

I use the diesel additive from Walmart. It breaks up particles so the filter can grab them.

I just took a suction on my tank and it's completely clean after sitting about 1/4 full for a few months.

I open the level sender, attach a hose to a rod and put it at the tank bottom. Then I connect the hose to my oil pump-out pump/fuel transfer pump (gear pump) and run it into a bucket.

The additive is about $12 for 100 gal. I add one in my 150 gal tank at every fill early on a trip with an old Racor. I then don't add more for the trip until the last fill. I change the Racor after first running a while on a trip.

I sometimes get slime but never saw that waxy looking yellow stuff.