Does my fuel have bacteria/fungus or asphaltenes? - SailNet Community
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post #1 of 45 Old 12-29-2019 Thread Starter
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Does my fuel have bacteria/fungus or asphaltenes?

With some time off work I've been catching up on my Practical Sailor reading. This months' issue (Dec 2019) has a report on fuel filters. No author is listed, but I suspect that @pdqaltair either wrote it or was closely involved in the testing.

I replace my Racor spin-on primary filter once a year, and last did it in late September 2019 (as described here). I had used about 35 gallons of fuel since the prior filter change (in August 2018). After changing it (a very messy job), I eliminated the last traces of air by operating the hand pump on the Racor housing a few dozen times. After doing that I was startled to see some crud which had apparently been hiding up around the rubber pump seals (or the brass hose barb fittings?) fall down into the perfectly clean bowl. I then reluctantly took the whole thing apart (another messy job) to capture the stuff that had fallen into the bowl. This is what it looked like:



I had been thinking all along that this apparent "petri dish cocktail" had to be bacteria, but was puzzled that I have never seen any sign of water in my fuel at all. After reading the PS article, I realized that it's possible that these particles are not biological, but instead are polymerized gunk from stale fuel (asphaltenes), which could be just what I had hiding out in the pump mechanism. The article mentions a good way to determine whether filtrate is biological or asphaltenes - just splash some bleach on it, and bacterial material will turn white while asaphaltene will be unaffected. I had disposed of my filter last September, but I retained the sludge from the Racor bowl, so I pulled out a hunk of that on a paper towel and splashed it with bleach. Here is what I found:

Before bleaching:



After bleaching:



Based on the absolute lack of change, it looks like it's not bacterial at all, which makes sense since I've not had any detectable water in the tank. I do realize that this does not prove an absense of bacteria, since it's possible that I have both bacteria and asphaltenes. But it's this brown stuff that has been the predominant material that clogs my Racor primary filter if I don't change it every 12 months.

Comments?

In another thread I mentioned that I have followed a practice of topping off my tank at layup to prevent breathing and condensation of the tank. Unfortunately this means the fuel is 6 months old by the time I launch, and a year old by the end of sailing season. (Plus, previous owner had left the boat unused for 1.5 years when I purchased it in 2016, and there was fuel in there the whole time.) This year the tank is nearly empty, and I plan to pump the remaining fuel out and inspect it, then fill about halfway with fresh fuel. Unless I discover that leaving the tank near-empty over the winter causes serious condensation, I will no longer top off, instead keeping a smaller quantity of fresher fuel in my tank. Comments?
Attached Thumbnails
Fuel Retain.JPG   Unbleached.JPG   Bleached.JPG  
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Re: Does my fuel have bacteria/fungus or asphaltenes?

How long did PS article suggest it would take for these to form in old diesel. It's my understanding that diesel is much more shelf stable than a winter layup would require. Still, I also find the condensation issue, for not having a full tank, to be partly myth. At best, it's dependent on individual climate, propensity for one's tank location to warm and cool, etc, etc. IIRC, @Maine Sail tried to recreate tank condensation in a test environment and could not.

The other factor I often wonder about is overdosing witchcraft additives and conflicts between them.
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post #3 of 45 Old 12-29-2019
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Re: Does my fuel have bacteria/fungus or asphaltenes?

Looks like bugs. Bleach will usually cause a color change, but not always, depending on what else is caught up in the floc (agglomeration of bugs). It is not the bugs that have color, it is whatever they absorb or floc with.

Contrary to popular wisdom--and I've spent 40 years in the petrol industry as a chemical engineer--a free water layer is not required for growth. It really helps, but is not an absolute requirement. All that is required is the finest emulsion, which you certainly do have from time to time.

There is not fixed time period for bugs. Like pouring new milk in an old jug, the bugs are in there. Other aging effect should take at least several years, unless there is free water and corrosion.

The only way to be certain is dip slide testing (Google). Alternatively, just start dosing with Biobor. You will get increase filter sludge for a while, as the dead bodies slough off.

T

---

Regarding condensation, this has been observed in the fuel industry for a century and is established fact. I have observed in the field (tank inspector) to the point of ruined tank roofs and I have recreated it in the lab. Typical sailor tests feature an empty tank--that is not realistic, because the drops that fall into the diesel in a real tank stay there, sealed in by the diesel, where as any droplets in an empty tank can evaporate. The temperature changes are also different.

If you want to eliminate it, use a silica gel vent filter. I believe they are one of the cheapest fuel quality investments for the occasional sailor. Or burn more fuel--it doesn't keep forever.

That said, it is very small amount, and water in the fuel nearly always comes from a bad filler seal or a poor vent design.
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Re: Does my fuel have bacteria/fungus or asphaltenes?

Quote:
Originally Posted by pdqaltair View Post
Looks like bugs. Bleach will usually cause a color change, but not always, depending on what else is caught up in the floc (agglomeration of bugs). It is not the bugs that have color, it is whatever they absorb or floc with.

Contrary to popular wisdom--and I've spent 40 years in the petrol industry as a chemical engineer--a free water layer is not required for growth. It really helps, but is not an absolute requirement. All that is required is the finest emulsion, which you certainly do have from time to time.

There is not fixed time period for bugs. Like pouring new milk in an old jug, the bugs are in there. Other aging effect should take at least several years, unless there is free water and corrosion.

The only way to be certain is dip slide testing (Google). Alternatively, just start dosing with Biobor. You will get increase filter sludge for a while, as the dead bodies slough off.

T

---

Regarding condensation, this has been observed in the fuel industry for a century and is established fact. I have observed in the field (tank inspector) to the point of ruined tank roofs and I have recreated it in the lab. Typical sailor tests feature an empty tank--that is not realistic, because the drops that fall into the diesel in a real tank stay there, sealed in by the diesel, where as any droplets in an empty tank can evaporate. The temperature changes are also different.

If you want to eliminate it, use a silica gel vent filter. I believe they are one of the cheapest fuel quality investments for the occasional sailor. Or burn more fuel--it doesn't keep forever.

That said, it is very small amount, and water in the fuel nearly always comes from a bad filler seal or a poor vent design.
Thanks for your comments!

What is the shelf life of Biobor JF? I've been dosing with it at every fill-up (carefully measuring based on how much fuel goes in). I did a double-dose (shock level) after last filter change. But the bottle came from PO, age unknown. Should I dump it and buy new BioBor?

I've looked at H2Out, but the install will be very difficult due to restricted space around my vent hose.

For now, I'm going to try fuel management so that my fuel is fresher (rinse the "milk jug" before refilling it). My prior top-off method prevented breathing, but the fuel was 6 months old before I'd launch, and CSTR calculations based on the consumption rate from a full tank show that average fuel age would be almost 3 years in the tank.

Is there a product that can solubilize water in diesel? I would not want to use such a product on an ongoing basis, but might put it in a couple gallons of diesel at the beginning of the season to try to remove any trace water that might be below my pickup tube. Then burn it off early in the season and put in 1/3-1/2 tank of fresh diesel.

To me, the most shocking thing was how all of that brown stuff in my picture dropped out of the pump mechanism of my Racor filter. If it's biological, there was a big colony hiding in there. I think I'm going to have to exercise that pump mechanism on a regular basis, which I had never done before.

I check my fill top O-rings regularly and the fuel tank one is pristine. Waste tank O-ring is not pristine, but I have not yet found a replacement that's the right dimensions.

Rick S., Swarthmore, PA
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Re: Does my fuel have bacteria/fungus or asphaltenes?

It is the only time I am thankful that I have a smaller sized ( 20 gallon) fuel tank. We run through the fuel fairly frequently enough so we donít have stale fuel issues. That coupled with the large amount of nautical miles we travel each year helps to also prevent fuel stagnation issues. Last year we used about 120 gallons of diesel in our 3000 nm. That represents approximately 180 hrs of engine time. I change the filters every 50 hrs.

I am a proponent of filling the tank To full before leaving for the winter. Since I have been doing that I find nary a trace of water in the fuel. I donít douse with large amounts of biocide either.

This works for us.

I know use of your boat is limited for you right now. I have found itís good to run our Yanmar with a good load. Iím not afraid to do that. I used to sail immediately and then all the way back to the dock. I have changed that somewhat to incorporate 1/2 hour out when leaving ( Iím in the Bay in 20 minutes from the slip) and also the same on returning. If I cant sail into an anchorage and anchor under sail I makes sure Mr Yanmar runs 20 minutes.


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Re: Does my fuel have bacteria/fungus or asphaltenes?

Quote:
Originally Posted by TakeFive View Post
Thanks for your comments!

What is the shelf life of Biobor JF? I've been dosing with it at every fill-up (carefully measuring based on how much fuel goes in). I did a double-dose (shock level) after last filter change. But the bottle came from PO, age unknown. Should I dump it and buy new BioBor?

I've looked at H2Out, but the install will be very difficult due to restricted space around my vent hose.

For now, I'm going to try fuel management so that my fuel is fresher (rinse the "milk jug" before refilling it). My prior top-off method prevented breathing, but the fuel was 6 months old before I'd launch, and CSTR calculations based on the consumption rate from a full tank show that average fuel age would be almost 3 years in the tank.

Is there a product that can solubilize water in diesel? I would not want to use such a product on an ongoing basis, but might put it in a couple gallons of diesel at the beginning of the season to try to remove any trace water that might be below my pickup tube. Then burn it off early in the season and put in 1/3-1/2 tank of fresh diesel.

To me, the most shocking thing was how all of that brown stuff in my picture dropped out of the pump mechanism of my Racor filter. If it's biological, there was a big colony hiding in there. I think I'm going to have to exercise that pump mechanism on a regular basis, which I had never done before.

I check my fill top O-rings regularly and the fuel tank one is pristine. Waste tank O-ring is not pristine, but I have not yet found a replacement that's the right dimensions.
Biobor JF shelf life is a long, long time. 10 years should be fine. Just watch for lumps.

[This diesel does NOT have bugs. It was exposed to air, water, and copper + zinc for 3 months. It is the metals that did it. Under more normal tank conditions, this typically takes 2-5 years.]


3 years is a long time for fuel. With storage times that long there are many problems.
*Bugs.
* Asphaltenes. This is a regional problem, and unless the refinery is making some very unstable diesel, is not generally a problem with modern ULSD. This is old news.
* Copper and Zinc. If ions get in the diesel they catalyze changes that look a lot like your pictures. EVERY major manufacture, including Yanmar and Cat, prohibit copper and zinc from stand-by diesel fuel installations. Google it or look here (Sail Delmarva: Are We the Cause of Fuel Breakdown?). See image above. The solution is dry fuel and a good anti-corrosion additive.

This might be the actual problem, since bleach will not alter these solids and they look much the same. You have old fuel, jelled by the combined action of copper, zinc, water, and time.

---

I've done a good bit of lab work on this topic, over many years. It only happens on boats that have long fuel space-times.

ASTM D975 Appendix X2.7.2: Fuel Storage Conditions
Copper and copper-containing alloys should be avoided. Copper can promote fuel degradation and may produce mercaptide gels. Zinc coatings can react with water or organic acids to form gels which rapidly clog filters.
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Last edited by pdqaltair; 12-29-2019 at 03:52 PM.
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Re: Does my fuel have bacteria/fungus or asphaltenes?

P- have 4 50g diesel tanks. Usually will run one down to 20% left then move to another one. Usually run the aft starboard first. Rarely run port forward down. Usually top off tanks once or twice a year. Have never run all tanks to empty. Havenít had a portable polisher out to boat since inception in 2013. Havenít had any troubles. Compulsive about biobor.

whatís best practice? Run tanks to empty?or leave 20% so you donít have sediment/water issues?
If youíre having no problems should you polish the entire contents of your tanks periodically? At what intervals?

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Re: Does my fuel have bacteria/fungus or asphaltenes?

Thats a lot of fuel/tanks to manage.
A big plus when needed

I would think...
Carry what you might use over 6 months..or x time period

Access to the inside of tanks seems to be a problem with many
Difficult to cure problems

Access to most things 'boat' is a pain
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Re: Does my fuel have bacteria/fungus or asphaltenes?

Access is actually quite good. All are under the sole. Just unlock and lift out a dedicated section for that purpose. Then unscrew access plate.
Thatís not the issue rather was looking forward to pdq advice on best practices. Many boats top off where and when they can. Old is mixed with new. Boats commonly go quite a long time on a fill or top off. Especially where itís windy. Sure you add biobor or like product but what else is advised to keep tanks clean, fuel that will burn nice and keep your engine happy.

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Re: Does my fuel have bacteria/fungus or asphaltenes?

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Access is actually quite good. All are under the sole. Just unlock and lift out a dedicated section for that purpose. Then unscrew access plate.
That’s not the issue rather was looking forward to pdq advice on best practices. Many boats top off where and when they can. Old is mixed with new. Boats commonly go quite a long time on a fill or top off. Especially where it’s windy. Sure you add biobor or like product but what else is advised to keep tanks clean, fuel that will burn nice and keep your engine happy.
There is no simple answer for keeping fuel fresh for >3 years, particularly when fresh fuel is being added to an inoculated tank. It's tough. The reasons trucks have fewer problems is that they burn the fuel!

I've done long-term testing, and although most fuel will keep in a sealed bottle for 10 years, some "turns" in a just few years under perfect conditions. If there is some air exchange, some water present, a few bacteria, and a few copper and zinc ions, the fuel is at high risk of changing in 3-5 years. The best you can do is:
* Silica gel vent filter. We can debate whether there is significant condensation, the fact of the mater is that the gel does absorb a few ounces per year. I think it is a good deal. Vent filters also reduce the amount of air moving in and out of the tank by convection (currents).
* Replace fill o-rings and put a little grease on them. If they are in a low spot, move the fill (I had a boat with a badly positioned fill that was in a rainwater path--it leaked no matter what and I moved it).
* Treat regularly with Biobor JF or any other biocide that is listed as a pesticide. I've tested many, and they all work. Biobor is my first choice. Do NOT wait until you have an infestation. Not only will you have to clean the tank, the dead bodies will go through your injectors, which is bad.
* Use double filtration, like a Raycor.
* Polish or don't. The evidence seems mixed (it treats the problem, but it's not clear it prevents the problem).
* Run the motor more. There is no substitute for turnover.
* To fill or not to fill. If you use a silica gel vent filter, I think there is no good argument in favor of filling. And the vent filter is cheaper than a fill-up!! Getting fresh fuel is better.
* Use a good anti-corrosion additive. It is the ions that make the fuel unstable (much testing, by ASTM, engine makers, and Practical Sailor).https://www.practical-sailor.com/iss...s_11083-1.html
* Avoid zinc and galvanized. Minimize copper alloys. I'm not sayin' rip stuff out... unless it is copper tubing fuel lines. The USCG got that all wrong, just ask the engine makers.

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Last edited by pdqaltair; 12-30-2019 at 05:58 PM.
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