Gunk in diesel fuel...how do I get rid of it?

[tadd5181]

I have discovered gunk in my diesel fuel.
I have a Racor R20S filter (plus one other) which reveals the gunk in filter's glass viewing area. I have had the fuel "cleaned" twice because of the gunk. This was done by a commercial fuel cleaning service. I faithfully have added a fuel additive to help stop the gunk from forming.
I have never discovered water in the Racor's glass view area.
The fuel cleaning involved draining all the fuel out of the 60 gallon tank on my 42' Hunter sloop, wiping out the gunky bottom of the fuel tank, and then refilling the tank. When emptying the tank for this cleaning, the fuel was filtered twice as the tank was emptied, and then filtered twice again as the fuel was pumpted back into the tank.
What is the gunk? Why does it form? Having had the fuel "cleaned" twice what do I do now? How do I keep from this happening?

 

[Buck420]

Tadd

You say .... "I have a Racor R20S filter (plus one other) which reveals the gunk in filter's glass viewing area"
What is the nature of the "gunk" and where do you see it in the racor's glass bowl??
You say "I have never discovered water in the Racor's glass view area" ; but if the "gunk" is at the bottom of the bowl than it IS (gunky) water.
If the "gunk" isn't at the bottom of the bowl, where are you seeing it???

 

[RichH]

The gunk is most probably the 'residue' (waste products, dead cells, etc.) from certain resin forming funguses and bacteria - Cladosporium Resinae, etc. .. common in 'fuel systems' that are vented to atmosphere.

How do you get rid of it?
Open the tank access ports, get in there with a long handled brush, knock all the gunk off the walls and to bottom where you soak it up with towels, etc. and then burn it all.
If you dont have access ports, sometimes you can drain the tank then use a long pressure washer 'wand' into the 'fill nozzle' to reach most of the spaces (behind baffles, etc.).

It may be hard to do but affect 'total' cleaning to ensure the least possibility of 'reinfection' you should 'more thoroughly' clean the tank .... and perhaps change your brand of 'biocide' as some biocides work better on 'some' bio species, less well on other species ... it really depends on the specific species that is dominating your tank.

How NOT to remove it:
Fuel polishing ... only (temporarily) cleans the oil; but, not the tank walls.
Using many many filter changeouts.

Once you return the tank back to 'hygiene', only keep in the tank the amount of oil that you need ... plus a wee bit of 'reserve'. Drain the tank when the boat is stored long term (winter) and take the oil home to burn in your oil furnace. Filling the tank for long term storage is NOT the answer; perhaps, accelerates the 'problem'. If possible never buy your fuel from a 'marina' but only 'fresh fuel' from a high turnover source such as that which caters to 'watermen' (or jug it in from truck stop).

A high 'faluting' solution to 'keep' the tank clean longer is to apply a microbiological blocking hydrophobic vent filter plus the addition of a water vapor adsorbing trap on the vent line AND use an onboard 'recirculation polishing' system.

Sorry but that gunk has to be manually scrubbed or blasted with a pressure washer ... no other way to do it.

 

[Steve Dion]

Build your own fuel polishing system.

You did not mention the fuel lines. Did you get these replaced too?

If you are having this type of problem you may want to think about the fuel polishing system that will run when your boat is tied to the dock. You can find these systems on the internet. They are not too expensive to build and much cheaper than having it done commercially.

http://www.trawlersandtrawlering.com/howto/captnwil.html

 

[Randy]

"Gunk" in tank

I own an antique diesel truck. Shortly after I purchased it I was having trouble with the engine (265hp Detroit Diesel) sputtering and running rough. I suspected an algae/bacteria problem, since the nature of antique trucks is to sit a long time (a week to a month at a timein my case) in between runs.

I took the following action: First, I used a heavy dose of biocide to help kill off anything that might be living or active in the tank. I added the treatment to the tank, ensuring it was well mixed, then ran the truck a while to circulate the treated fuel throughout the fuel system. I let it sit a week to ensure that anything living in the tank was good and dead before the next step.

After the week was up I changed the fuel filters (primary and secondary, just like a boat), and manually cleaned the filter housings (they were full of gunk, much like you describe.) I also drained the fuel tank. Since this is a truck, draining it was easy--I can crawl under the truck and remove the drain plug in the bottom of the tank, draining it into a barrel. This gets 99% of the fuel out, plus any sediment or "gunk". The one thing I can't do is scrub the inside of the tank--there are no access ports, and removing the tank was not an option ($). I disposed of the old fuel, and added new, fresh fuel which I jugged in from a high volume supplier (ensuring its freshness).

While discussing this truck problem with a fellow boat owner, he recommended the use of Startron Diesel Fuel additive. It's an enzyme based treatment, which breaks down the water or moisture in the tank (however much or little there might be) then "eats" (for lack of a better term) the residue (gunk) that's in the tank, lines, and filter housings. I have been adding a dose of Startron to the tank anytime I add fuel (which I always bring in by the jug).

It's been two years since I drained the tank and began using Startron, and I have had no fuel problems. The engine is smoother, more powerful, and does not sputter. I am furiously knocking on wood as I type this, but I believe it is due to the Startron.

At the same time I began using the Startron on the truck, I began using it in the boat (14hp Universal M-18 diesel) and I have not had any fuel problems, even though the last two years have been extremely low usage years for me (I have two young children who are not sailors--yet). This means the fuel sits, much like the truck, for long periods of time before being burned. Knock on wood, using Startron seems to work for me. Several years ago I did drain the tank on the boat, but had to siphon the fuel out (typical for most boats), then added fresh fuel. The siphoning does not get all the "stuff" out, or even all the old fuel. Again, I believe it was the Startron that has prevented any problems for so long, combined of course with regular changes of the primary and secondary fuel filters.

I know there are naysayers, and those who believe you should never put an additive in a fuel tank. "Just use fresh fuel," they say. But the nature of most boats (and antique trucks) means that even fresh fuel is going to be stale by the end of the season. This is especially true of sailboats (mine burns .25 to .50 gallons per hour). Therefore I have elected to use the Startron, and I believe it works.

Your mileage may vary, as they say, but give it some consideration.

Good luck,

Randy

 

[rfrye1]

Tadd, I just went thru this (also in San Diego). Perhaps where we get our fuel has issues? My last fuel purchases have been at Harbor Island and also Shelter Island over by the Red Sail Inn. Just a thought. Bob

 

[sailaway78]

Are you sure

Are you sure there is actually any "gunk" in the tank and fuel system? I have seen those clear filter bowls get kind of dirty looking, or discolored, with nothing at all harmful in them. I think maybe it is from some of the dye they put in the off road fuel. When you drain the bowl, is there any crud in there? Do the filters get stopped up? Does the engine run bad? What do the filters look like when pulled out? Drain the bowl into a clear glass container, and see if anything settles out, or any particles reflect light. Wipe out the bowl, and see what you get on a rag. Just discoloration is not something to worry about. I am not one to leave needed maintenance undone, but I also am of the if it ain't broke don't fix it school. If you do not have a problem with filters plugging up, and the engine runs good, leave it alone.

 

[tadd5181]

Re: Tadd

I have had the viewing area viewed by two experts who say what is seen is definitely not water. It looks like fuzz or dark clouds, and it lies, unevenly, at the bottom of the viewing bowl.

 

[RichH]

Re: Are you sure

Tadd
"experts" come at a price. Unless they did microscopic or turbidity analysis or even small sample 'fiter disc' testing all bets are off if its water, contaminated tank or contaminated fuel, etc. etc. "fuzzy stuff" doesnt count. Water can be in fuel in various 'states' and it doesnt necessarily have to be layered/settled in bottom of the 'bowl' to be 'water'.

Since you had some measure of tank cleaning which should yield some 'resident' particle reduction in the tank .... go back to your 'usual' supply source, buy 1/2 gallon, pour it into a clean container, bring it home and pour it into a clean/clear glass, etc. Hold the fuel up to BRIGHT white light (the glass held between your eye and the light). If there is any visible 'haze' to the fuel - its your supplier's problem - contaminated supply tanks, 'bad load of fuel', etc. If the sample from the normal supplier is almost 'crystal clear', then your tank has 're-infected' / recontaminated ... (such particles 'grow' or agglomerate -- extremely small particles coming together to form larger and larger particles, etc. ... and you need to clean the tank better / more completely this time.

If you are 'over-filtering' (using a 2µM filter instead of a 10µM), sometimes/rarely the action of the 'too tight' filters will 'coalesce' small and nearly invisible deformable particles (gels) into larger and larger visible particles (as a 'coalescence'). Visibly clear fuel is at a resident particle distribution size that is approaching 'sub-micronic'. A filter only does its job by capturing various forms of debris .... that 'debris' that you see in the bottom of the clear sump in the bottom of the filter 'may' only be a 'concentration' (filter doing 'crude gravimetric separation') in the sump chamber before the fuel enters the filter media ..... and this 'concentration' of debris may actually be normal for your 'brand' of fuel ... if the tank has remained clean and the supplier is dispensing clean fuel. How many total gallons have passed through this filter sump before you noticed 'the problem'?

As another poster stated, if the fuel is not plugging the filters (rapidly changing the gage values that monitor the filters) then you probably picked up (and repeated) a load of bad fuel, or your tank has become recontaminated OR what you see in that 'clear' filter bowl is 'normal'.
Filtration of fuels, by refiner, depot, your supplier and your RACORS is a crude and not a 'precise' filtration that removes ALL the particles at every step. That concentration of now captured/separated 'escapees' may be what you are noticing in that filter sump. Its totally OK for filters to get dirty and accumulate 'junk in the sump' .... thats the job of the filter !!!!!!

 

[Stillraining]

Re: Are you sure

Wow...maybe I'm in for a new education here..being new to desiel on saltwater

I'm an excavation contractor.....I have 17 pieces of heavy equipment...I use to have employees but for the past 3 years have been on my own...needless to say I have a lot of equipment that sits for way longer then a month.

I just picked up not one week ago...one of our Dozers that has sat in a customer's back yard for 6 months... without so much as giving it 2 seconds thought about sitting there that long..2 revolutions it was running ( Batteries sat 6 months too but I wont get into that cuz I know how you all are with your batteries too) and after 5 min warm up I loaded it up and took it to a new job where I ran it for 6 hours straight before refueling it.

I do this kind of stuff all the time..In years past we have had pieces of equipment down for as long as two years and once repaired fired them up and burned the remaining fuel with zero issues not even bothering to change the filters..

The only time we ever had an issue is one year we converted a 1200 gal commercial fertilizer spray truck into an on site fuel truck..it did get an infestation of the bugs you all talk about..I regarded that to the fact that other contaminates and fertilizer residues were already in the tank and gave way to the incubation of the things..

Maybe we don't have as big of an issue around these parts due to the climate or something..but I'm not going to worry about it in the boat till it happens ...I sure hope its not education time soon.

I hold 120 fuel on board I'll be filling up next week which should last me a year or better and I know of quite a few other boaters around here that fuel up once per year also..Hope I'm not screwing up but my experience says...NOT...

I do worry about gas going bad in things sitting around...but never diesel.

I have sat on one machine or another day in and day out for the past 22 years in my own business and longer before that...no sir...Diesel has served me pretty well for 30+ years now...Take it for what it's worth.

Your bugs may very

PS: I'M going to go out this week and fire up that said old fuel truck...It has sat now those 3 years with out being touched..I'll update you on what happens.

 

[Buck420]

Tadd

I respect what everyone has said in this thread... alot of good info and thoughts.
Another thing that I found interesting in your initial post was your comment:
"I have never discovered water in the Racor's glass view area" ...
WOW, I don't think I've ever met a boater (or diesel engine operator) who hasn't found water in his recor at least occasionally.
This fuzzy, cloudy,, "gunk" you see in the glass bowl of your Racor; does it drain out w/ the fuel or does only fuel come out and this "stuff" remain as a coating on the inside of the bowl?
If it drains out, does it eventually settle to (or near) the bottom of the container you drained the bowls' contents into??...
I'm certainly not nearly the expert that others are, but like "Stillraining", after 25 years of observation and dealing w/ diesel engine problems, I still think it's probably a gunky mixture of water and other hydrophillic "stuff".
BTW, you didn't mention what effect this "gunk" is having on how the engine runs.

 

[MoonSailer]

Re: Tadd

I think that a little gunk is normal in fuel. I keep my tank about 1/4 full and add 5 gallons at a time as needed. Once a year or so I change my filter. The most water I have ever detected was just a few drops. If it was my boat and the filters are not clogging too often and th engine runs OK I would run the tank almost dry and then just keep enough fuel in the tank to last a few months. A 60 gallon tank is way too much fuel for the average sailer. 60 gallons would probably last me 6 years of average sailing. I typically use 10-15 gallons/year except when taking a trip that requires a lot of motoring. In my defense I have taken to motoring an hour or so once a month or so just to run the engine. But on a typical day I run the engine 15 minutes to get out and raise the sails and then another 15 minutes at the end of the day. This past weekend I motored about an hour when the wind died and I was about 6-7 miles from the dock. BTW it was great to have an autopilot!!!! I set the engine to 1200 rpm and the autopilot to 290 degrees and sat up on the deck to watch the sun set!!!! With the moon rising in the east at the same time it was a great evening.

 

[Steve Dion]

Tadd:

Here is another option. Get enough jerry cans to empty your tank and filter everything through one of these units.

http://shop.sailboatowners.com/detail.htm?fno=400&group=812

Cheap enough to try and it is going to clean up the fuel for now.