Orange discharge from fuel tank vents

[Cheechako]

being a "new to you" boat and a powerboat, I would consider having the fuel polished and be done with it.

[Le Tour]

I have not had the fuel polishing done before but I plan on looking into it. I am familiar with dealing with a 20 gallon fuel tank on my old boat, but 400 gallons is another matter. Although many bacteria are less than 2 microns I believe these diesel bugs are larger. They appear to have been caught by the 2 micron Racor, but to be certain I need to open the downstream filter on the Cummins. I have seen a few references on the CF site to building a fuel polisher and need to look into this. I am not certain about the cost for a 3rd party do the job on 400 gallons or wether this contamination will be an infrequent occurrence going forward. Given my low rate of fuel consumption I will likely use a fuel treatment in the future so I still need a good biocide recommendation and I suppose I can add to that a filter pore size recommendation as well. Thanks again for the responses.

[thinwater]

a. Bugs are all sub-micron. Clumps can be larger.

b. Bugs are basically colorless; color is from things they pick-up (in this case ferric hydroxide from iron which they help corrode). Often they turn black when they "die" because in the absence of oxygen the ferric converts to ferrous, which is black. It is actually more complicated than that, but the point is don't judge based upon color.

c. There is some test data here.
Sail Delmarva: Diesel and Biocides

d. The biocides won't help with the corrosion issue. Separate additive for that. Star Tron + Biobor has tested well.

[chrisjs]

It sounds as though you do not necessarily have "dirty" fuel or need at tank cleaning. Before you spend that sort of cash, check the following. First, check the filters - it sounds like you have clean filters, so it seems unlikely that you have either dirty fuel or dirty tanks. Second, if possible, transfer enough fuel from one tank to the other to "overfill" that tank enough to displace fuel out of your overflow -- make sure no fuel enters the water - until "clean" fuel exits the overflow. Do this for both tanks. If the volume of crap is small the problem is almost certainly just in the fuel vent lines. If so, my guess is that wind driven rain entered the vent lines during a storm and has festered in the line mixed with fuel remnants. Suggest you simply flush out with clean diesel as previous until all crap has been pushed out. Do this and just keep an eye on your Racors. If there is no water/pink crap in the Racors going forward you do not have a fuel problem.

[DeepFrz]

You wont know what kind of problem (or no problem) for sure until you open your tanks and check them out. Leaving dirty crud in your tank, like biota, after using a biocide is just plain waiting for the filters to plug up at exactly the wrong time. Putting in a biocide just kills the bacteria. They settle to the bottom and form a mass on the tank bottom and sides. Hitting some heavy water can slosh the fuel around and voila, plugged filter or plugged pickup tube. Not a fun thing in a seaway.

[Le Tour]

[QUOTE="thinwater;1188407"]a. Bugs are all sub-micron.

c. There is some test data here.
Sail Delmarva: Diesel and Biocides

/QUOTE]

Thanks for the very informative and well written reference. It answered quite a few questions.

[Le Tour]

Originally Posted by DeepFrz

You wont know what kind of problem (or no problem) for sure until you open your tanks and check them out. Leaving dirty crud in your tank ... Not a fun thing in a seaway.

Yes, this is good advice. There is no substitution for seeing the extent of the issue with the naked eye. Until that is done the ultimate solution is just speculation.

[Cheechako]

Once when I had a new-to-me boat, after servicing the dual Racors, I thought; " I should really check that final filter that is on the engine". I put it off for a few weeks thinking "how could anything get that far", plus I had to research and get the proper filter. The boat ran fine.
When I finally serviced it, the filter housing was completely full of an opaque tan/cream colored jello like substance. Evidently it had been a long time and things were growing well in there. Amazing that it ran at all.... yet it had no ill effects.

[Cheechako]

Cool, thanks for sharing.

[shorebird]

I doubt if the discharge is rusty water, since water settles to the bottom of the tank, as pointed out. It is almost certainly fuel with a microbial growth, but you can simply feel the stuff, diesel fuel is slippery, water, not so much. Fuel polishing can be very costly, and last year I cancelled an appointment with a fuel polishing company that charged my neighbor $800 for a 20 gallon tank, and did it myself.
I used a Fillrite 15 gpm 12v pump, contained in a plastic tote, and ran through a water block 20 micron filter with a clear water settling bowl. I ran both a pickup and discharge hose into the tank at enough flow volume to agitate and dislodge accumulated "gunk" and water in my fuel tank, changed the filter element when the flow was reduced, and continued for several minutes.( Larger tanks likely have baffles, and this may not work as well.) You can check for water in your tank(s) by using "water finding paste" which starts grey, but turns bright red in the presence of water. Remove any water you find in your tank(s) find and eliminate the source of the water, (often a poor seal at the fill cap) and use bacteriastatic fuel additives, rather than bacteriacidal additives, which is often just the dosage.
The long held belief that tanks should remain full during the winter to prevent water ingress from condensation is being reconsidered in view of the condition of the fuel left sitting all winter vs the miniscule amount of water condensing in the tank.

[shorebird]

I'm a bulk fuel tank manufacturer, (wwwtidytanks.com) so I'll look at your product and testing a little closer.
cheers,
David

[chrisjs]

LT: Still not convinced you actually have a fuel contamination problem. Black "stuff" on the Racors is normal. Unless you are clogging filters rapidly and/or see the orange color in the Racor bowls, I would begin by exploring the vent piping for rust/water or fuel/water. It is quite possible that water is getting blown into the vent and causing your problem. Begin with the easy-to-do things! Why do you think your tanks are contaminated? You do not appear to have any evidence of that from what you have posted.

[Le Tour]

Originally Posted by chrisjs

LT: Still not convinced you actually have a fuel contamination problem. Black "stuff" on the Racors is normal. Unless you are clogging filters rapidly and/or see the orange color in the Racor bowls, I would begin by exploring the vent piping for rust/water or fuel/water. It is quite possible that water is getting blown into the vent and causing your problem. Begin with the easy-to-do things! Why do you think your tanks are contaminated? You do not appear to have any evidence of that from what you have posted.

I am not totally convinced either and will start with the easy, low-cost approaches like cleaning the vent lines and ensuring there are no low points. In the past 17 years I have never used biocide. However in researching this it appears that diesel fuel formulas have recently changed to reduce emissions, but that change might have made them more susceptible to bio growth. So, I thought I would look into what kinds of biocides and fuel treatments are being used by others with good first hand success. The cost of biocide treatment appears to be very low. Nonetheless, I don't want to throw something in the tanks w/o a little research and first hand guidance. The notion of fuel polishing is also interesting and this excellent forum has provided plenty of "fuel" for thought.

[Aloha_float]

Originally Posted by shorebird

I'm a bulk fuel tank manufacturer, (wwwtidytanks.com) so I'll look at your product and testing a little closer.
cheers,
David

David, are you in BC? We talked to somebody at Tidy Tanks. I can check who it was once I get back to my office.

[Le Tour]

I placed the original posting on this thread back in March and would like to provide a quick update. First, I'd like to thank those of you who responded to my query. I took the advice of Aloha-Float and read up on Fuel Rite. It appeared to be a good product for breaking up the dead bacterial matter that can clog fuel filters, injectors etc. I purchased the product, mixed the appropriate amount to treat 400 gallons of fuel with a few gallons of deisel fuel and poured it into my tanks. I also purchased Racor's Killem biocide to treat the live cultures within the tanks. I let the products do their work for 3.5 months while I used Le Tour (in some rough weather), ready to change filters if needed. Last week I changed the Racor's and engine filters on the Cummins and Northern Lights Genset. The filters and Racor bowls looked remarkably clean, nothing at all like back in March. I also did not observe any orange discharge while refueling. So far so good. Thanks again for the comments and advice.