DYI Fuel Polishing Issues

[JSSailem]

Have 150 gallons of fuel in two tanks that I believe has the pox of diesel fuel critters. Age of fuel is unknown, likely more than 2 years. So filtering the critters is planned. Knowing this is a first time event for me I've been researching ideas. Have located a pump and filter system the manufacturer identified for use with oils and hydraulic fluids. Diesel not mentioned as US manufacturer did not file for EPA/etc permits.

Ideas solicited from this boat experienced crowd. What are your thoughts?

Planned System would provide 7 gpm flow that will in 1.5 hours cycle the fuel in one tank 6 times (includes anticipated set-up, monitoring, 3 plus filter changes). Sure there would be changing filters but should get at least an 80% polish on the fuel. The process likely could induce air into the fuel, an issue and concern? Need for fire extinguishers, and fuel spill planning of course.

What else am I missing?

Grounding questions. Wires connecting pump - nozzle/fuel filler wand - fuel tank. (what else). Tanks are located in fiberglass 35ft boat. Thinking to use fuel level sender opening to withdraw and return fuel to tank. (about 2" hole in tank top) Could also run hose into deck fill access.
Thoughts regarding protecting against static charge buildup?

Alternative is to pay a guy $900 to come out and do the task.

[dlymn]

check that the pump will run continuosly for 1.5 hours

[thinwater]

Originally Posted by JSSailem

Have 150 gallons of fuel in two tanks that I believe has the pox of diesel fuel critters. Age of fuel is unknown, likely more than 2 years. So filtering the critters is planned. Knowing this is a first time event for me I've been researching ideas. Have located a pump and filter system the manufacturer identified for use with oils and hydraulic fluids. Diesel not mentioned as US manufacturer did not file for EPA/etc permits.

Ideas solicited from this boat experienced crowd. What are your thoughts?

Planned System would provide 7 gpm flow that will in 1.5 hours cycle the fuel in one tank 6 times (includes anticipated set-up, monitoring, 3 plus filter changes). Sure there would be changing filters but should get at least an 80% polish on the fuel. The process likely could induce air into the fuel, an issue and concern? Need for fire extinguishers, and fuel spill planning of course.

What else am I missing?

Grounding questions. Wires connecting pump - nozzle/fuel filler wand - fuel tank. (what else). Tanks are located in fiberglass 35ft boat. Thinking to use fuel level sender opening to withdraw and return fuel to tank. (about 2" hole in tank top) Could also run hose into deck fill access.
Thoughts regarding protecting against static charge buildup?

Alternative is to pay a guy $900 to come out and do the task.

Diesel, particularly contaminated diesel, is generally too conductive to build static (gasoline and jet fuel, yes), so static bonding is not a big concern, though still a good idea. Using CPVC for the wand and fuel hose solves the problem (CPVC is sufficiently conductive, PVC is not). Aluminum can also be used as a wand, though surprisingly, it is not as safe as CPVC (more spark potential).

You cannot actually filter out all of the bugs (they are sub-micron and many will stay on the walls), so you will be a course of biocide. Biobor and Raycor are both good, though like antibiotics, the best choice depends on exactly which bugs you have.

The best answer is to burn the fuel down (perhaps after some polishing) and then clean the tank manually. Polishing will NOT remove build up on the walls, bottom, or in the lines.

---

Obviously, future prevention is the ticket.

[Vasco]

When I had my fuel polished the guy put the fuel back into the tank under a bit of pressure and blasted all the crud off the bottom and sides of the tank. Just polishing the fuel is not enough, you also have to make sure the tank is clean. He first polished the fuel and put it into his own tanks then cleaned the tank and then put the fuel back into my tank.

$900 sounds a bit high.

[Matt Johnson]

We got two 55 gallon plastic drums off craigslist and pumped our 10 year old diesel into them through two filters. We then used a shop vac, toilet brush and a rag on a stick to manually clean all the surfaces down. While we were manually cleaning the tank, we were polishing the 55 gallon drum over and over.

Worked well, but we had good access to the inside of the tank.

Matt

Sent from my LG-V410 using Cruisers Sailing Forum mobile app

[Lepke]

The main issue is to kill any growth and filter it out. Any marine growth on the tank sides will be killed and eventually be caught by a proper filtering system. I am 67 and been around diesels since I was 7. I have never had to enter a diesel tank to clean. But I have been in many tanks for repair and salvage purposes. I've never had a dirty fuel problem in my life.
Using a good biocide and filter system will clean the fuel without elbow grease. My current boat sat 6 years w/o any biocide/fuel conditioner. Without tearing apart several cabins, tanks were not accessible. Using a triple dose of Algae-x, Racor 30 micron filter, and a 35 gallon/hr pump, circulated the tanks (2000 gallons in 4 tanks) for several hours each. Most were near empty. Before engine starting I added about 10% fresh fuel in each tank. Changed all filters and never had a problem. Two years later when remodeling allowed getting to the tank tops, I entered all the tanks and found them clean, no growth, a little surface rust (1942 steel tanks) and some deep pits in the bottom I welded up.
Because I only buy from places with clean fuel (and a problem with my heating boiler's jet plugging) my Racors have 2 micron filters. I have a gauge to show when the filters are getting dirty, usually about 500 hours. I use a fuel conditioner all the time. Secondary filters never get dirty.

[Nicholson58]

We lost our HP injector pump from silted oil and dirt. I studied this for awhile and found good discussion on trawlers forum and for over the road truckers. I installed a FRANZ filter with a 45 gph pump. The FRANZ polishes to one micron. Many flow circuits are possible but for us, the following. Fuel is sucked up by the new pump from a low dip tube in the 70 gallon day tank. Fuel from the pump is forced through the FRANZ a filter. Clean oil goes to both the main engine and generator primary inlet ahead of the RACOR filters. The excess clean oil returns to the tank through the dip tubes for each engine. If there is a polishing pump failure the engines get fuel as they always have. With multiple tanks you could return to a different tank but beware that you don't flood the secondary tank!

[RaymondR]

I did my first polish about 15 years ago after moving to a new cruising ground where the water was warmer. I used a 12V impeller pump and clear 1/2" tube over the end of which I had tied a cloth bag about 3" in diameter and a foot long made from denim. I made a water trap from a 20 litre plastic chemical drum by drilling a hole slightly smaller than the 1/2" return tube which I forced into the hole about 2/3 up from the bottom.


I circulated the tanks through the Rube Goldberg arrangement for about three hours and removed about 2 gallons of dirty water and three of four bags full of slimy gunk from the bag. I did not have a problem again until just recently when I found a fair bit of water in the tank after changing the stand pipe.


The Rube Goldberg arrangement worked so well I built a smaller permanent one using a spaghetti storage jar so that I can see the water level in it and keep the water drained down. The thick, tight weave of denim appears to make a good filtration medium however I don't have a clue regarding the micron particle size cut it provides.


I now use a 12V gear pump to circulate the fuel and also use the same pump to drain the oil from my engine for oil changes.

[yachtgemini]

If you have a really bad build up including jelly etc you can expect to use many fuel filters.

Before I started polishing I stirred the fuel up really hard to get the maximum amount of particles into suspension.

Having had this problem before I found it more economical to use a baja filter stuck into the deck filler for the first few passes.This gave me a chance to simply tip some of the worst into a bucket. You also get a good look at what is in the tank.

I used high flow rate gear pump fed by a hose with a long aluminium tube that I could poke around the very bottom of the tank attached to a long hose run out through a hatch to baja stuck in a deck filler. Once the flow into the baja filter was clear I then inserted a 30 micron racor and after clogging a few of these moved to a ten micron.

Come back to the job a few days later and use a very slow / low flow rate pump and then use a water seperator / filter. I was very surprised that I pulled about 1% by volume of water from the tank of fuel that had already been polished. As the fuel bug needs water to grow it is critical to get the moisture out and 'bomb' the tank with a treatment dose of biocide.

We had taken fuel in Malaysia and it was so bad that we clogged all our filters within 10 minutes of leaving the dock. It seems we got the bottom of their tank and that they had removed their filters because they kept getting blocked. Once infected with the bug it took us a good few months and 3-4 polishing sessions and lots of biocide to get and keep the tank clean.

[DeepFrz]

If you run the return line down to near the bottom of the tank you will minimize/eliminate aeration of the fuel. Nothing works better than a manual cleaning of the tank as well as the filtering by successively smaller micron filters, 30 then 10 micron and maybe even 2 micron for the final filtering. Manual cleaning of course requires good access to all parts of the tank, which may be problematic. If possible install a proper port in the top of the tank.

[Cheechako]

Emptying and cleaning the tanks with pressure is good thing if you are as cruded up as you indicate.
There are filter units available for about $25 with cartridges about $6-7 available. You are going to need to change filters a lot as they will crud up. Using those cheap filters should work fine. They are big too which is a good thing.

[kmcshane]

This was my scheme
You can see I had adquate access the the tank (22 x 16 cm roughly).
Rubber hose to the bottom of tank, up to the Racor with 30 micron filter, pulled through the 12V pump, and dumped into the jerry can.
I used two jerry cans so that as one was filling, I was using the other one to fill up the 37 gallon fuel tank on my diesel pickup truck.
I "polished" 75 gallons from my two onboard tanks, then wiped both tanks clean as a whistle with cloth rags. Even used some kinda chlorine bleach spray for the mildrew-looking discoloration on the sides and bottom of both tanks.
I did have one hiccough...I should have replaced the rubber O-ring on the diesel filler Perko cap on the deck. Some water got in that way, after all my "polishing." BTW, the truck ran fine, and I refilled my fuel tanks with fresh.

[bsurvey]

why take chance with unkown age


give it to an oil recycler they will come out with the tank truck and pump it out


then you can clean the tank. less expense than polishing

[Pete7]

Originally Posted by Lepke

The main issue is to kill any growth and filter it out. Any marine growth on the tank sides will be killed and eventually be caught by a proper filtering system. I am 67 and been around diesels since I was 7. I have never had to enter a diesel tank to clean. But I have been in many tanks for repair and salvage purposes. I've never had a dirty fuel problem in my life.
Using a good biocide and filter system will clean the fuel without elbow grease. My current boat sat 6 years w/o any biocide/fuel conditioner. Without tearing apart several cabins, tanks were not accessible. Using a triple dose of Algae-x, Racor 30 micron filter, and a 35 gallon/hr pump, circulated the tanks (2000 gallons in 4 tanks) for several hours each. Most were near empty. Before engine starting I added about 10% fresh fuel in each tank. Changed all filters and never had a problem. Two years later when remodeling allowed getting to the tank tops, I entered all the tanks and found them clean, no growth, a little surface rust (1942 steel tanks) and some deep pits in the bottom I welded up.
Because I only buy from places with clean fuel (and a problem with my heating boiler's jet plugging) my Racors have 2 micron filters. I have a gauge to show when the filters are getting dirty, usually about 500 hours. I use a fuel conditioner all the time. Secondary filters never get dirty.

I disagree, filtering as others have said isn't enough.

This was my yachts fuel tank despite filtering the fuel regularly and there being no sign of a problem. The only reason I opened the tank was out of curiosity. There is no way any filtering will move this unless some form of high pressure jet is used to wash it off the sides and bottom of the tank. For information the consistency was that of custard.

The solution was to open up the tank via the inspection hatch and if a tank doesn't have one then it needs one fitted. Then armed with a 2" wall paper scraper remove the gloop followed by lots of cleaning with rags. Finally wash down with clean diesel and dose with Marine 16. No problems since but filtering wouldn't and didn't resolve this problem.

Before



After manual cleaning:

[JSSailem]

Thank you Pete7, And the rest of your great guys.
Looks, as I suspected, I have some work to do. I am going to try and get through this season so I can get some boat use and then address the tanks. I put a hole in the starboard tank so I could put an intake for my diesel heater. The metal was something else. Tore up one of my bi-metal bits. It is painted and dates from about 1974. Not sure what material was used, but it was a tough bugger.

Cutting in inspections ports is going to take some time. I suspect there are internal baffles but not sure where. So this will need time and planning.

Then of course the fun removing the gunk. The joy of finding an old boat and trying to restore her.

No one made much comment about the hazards of the job. While I am encouraged that diesel is not normally explosive I have read some scary stories of fluid explosions touched off by static. With the tanks mostly full there is little space for air/fuel vapor. I intend to have both hoses under the fuel to further reduce any air spark issues. The hoses I received from a oil fluids company are labeled PVC with a reinforcing wire.

An issue in anyone's experience?

Pump is A/C and rated for continuous use. Italian manufacture giving it a rating for diesel. I found a couple of large filters and spares.

It is an experiment that I hope doesn't kill me.