The Best Fuel Filtering Ever!

[Delancey]

Now that my fuel tank is squeaky clean I am interested in hearing opinions about what constitutes best possible fuel filtering set-up. I've got an old 44hp Universal diesel.

The boat came with a fuel pump after the tank and before a 2 micron Racor before a 10 micron WIX on the engine, go figure? The fuel pump has a plastic screen and a magnet which was covered with rusty bits, the fuel tank is aluminum.

Pre-filtering before the tank with a Baja type filter seems like a no brainer, but then what?

Filter before the fuel pump? Dual Racors with the ability to switch from one to the other? Keep the 10 micron filter and put it before the Racor? Leave the two filters after the fuel pump? What size filters? Vacuum gauge on the Racor?

If I have really great filtering from the get go is "fuel polishing" really necessary assuming I am using biocide additives? Now is the perfect time to do whatever I want, what do I want to do?

[resilientg]

BUILD A FUEL POLISHING SYSTEM,...simple

all you need is a one or a pair of water filter canisters (Like you use at home under your sink etc), filters of the micron size your after an inline pump, some hose and valves, you can even set a timer to it to automate it when your not on the boat.

That way all your fuel can get "polished" at the flick of a switch, keeps everything cleaner and nicer and less opportunity for problems.

try to Google fuel polishing to get an understanding of the systems available then try YouTube to see what other people have made.

Matthew

[David M]

I have a dual Racor system with vacuum gauges and water alarms. I'm happy with it.

I don't think that fuel polishing necessarily replaces a biocide additive. You can do one, the other, or both. I think it mostly depends on whether or not you are having a problem with bacteria or other debris in the fuel and the amount. Remember that Diesels already do some polishing on their own because they do not burn all that they receive. Some fuel is sent back to the tank via the return line.

Use the mesh size filter size that your engine manufacturer requires. Going smaller than that is unnecessary. Most people don't need smaller than ten microns. Going smaller than needed only means you wlll have to change your filters more often and accomplish nothing other than that.

[DeepFrz]

Seaboard Marine - Tony's Tips | Marine Fuel Filtration - “The Seaboard Way”

Actually, filtering down to a nominal 2 mic level probably could have some quantifiable benefits ( injector seat & injection plunger/cam wear), even for and an engine that does not require that level of filtration. But this is not the reason I sell replacement injection pumps a couple of times a year and rebuilt injectors about 10 times a year. It's because of water contamination, and the fact that the operator only relied on his 1st line of defense (typically a "RACOR") and the marketing hype around it that led to complacency regarding fuel quality... So, I'm not going to argue about whether filtering below manufacturers' specs has a benefit - what I'll argue is the way most people filter fuel. And, that typically is that the vessel and / or operator is relying on a single filter to remove water and contaminants before he sends that "filtered" fuel to his on-engine" last chance fuel filter - This is a major mistake in judgment as to think that the last chance filter will save him. We hope to convince our customers that a well designed fuel system will deliver fuel to the engine, and to it's "on-engine fuel filter", that is all ready clean enough that he is not relying on this "last chance" filter to save him.

I would suggest you read the article at the link.

[Aloha_float]

Read article ... Good advice

Biggest pet peeve....when someone states that "algae" is in the fuel. Algae does NOT grow in fuel. Two things grow in diesel fuel. 1. Biomass which is a complex environment of aerobic and anaerobic bacteria that are bound together with expo polysaccharides. FYI, biocides are not effective at breaking down this growth. We know it as "sludge"
2. Different forms of fungi may grow in a fuel tank. It typically will look stringy and can be treated with biocides such as kathon.

[David M]

Nearly all algae is photosynthetic. It is oil digesting bacteria that can be found in Diesel.

http://microbewiki.kenyon.edu/index.php/Alcanivorax

[Aloha_float]

@ David

This bacteria is not the same bacteria found in diesel fuel. The following is a common list of bacteria typically found in diesel fuels. They work together to build complex colonies that we know as sludge. It is typically opaque and only takes on the colour when either diesel is degraded to food for some of these bacterium or picks up pigments from its environment such as oxides.

Bacteria Fungi
Bacteria and Pseudomonas species1 Hormoconis resinae2
Fungi Commonly Flavobacterium species Fusarium species
Recovered from Sarcina species Candida species
Diesel Fuel Desulfovibrio species Aspergillus species
Desulfotomaculum species
Hydrogenomonas species
Clostridium species

It's a long discussion....

you are correct about algae and photosynthesis.

[Irish rambler]

One of the biggest problems with boat fuel is that it doesn't turn over quick enough but often lies in a boat tank for (in some cases) years. Trucks don't have the same problems because the fuel is used quickly and therefore kept fresh. Start at the source of problem, the fuel tank installation, the tank should have an accessible drain cock fitted to a sump and be drained for water/dirt regularly. Fuel is like fine wine, it contains very fine particles of sediment and minute amounts of water that settle to the bottom of the tank, the 'diesel bug' grow at the fuel/water interface in the bottom of the tank. Condensation on the interior of boats fuel tank exagerates the problem. To avoid condensation keep the fuel tanks full particularly over winter and/or insulate the tank, I use simple fireproof 'stick on' expanded polyurethane sheets. A prefilter/water trap( I use Caterpillar) and the engine manufacturers recommended engine filter are all that are needed. K.I.S.S. Racor and other fancy filter systems are quite frankly a waste of money and simply not necessary. If cruising in a strange area take a tiny sample bottle of fuel when filling, put on a date/time/place sticker,get the vendor to initial it, if you have problems you can nail the guy later for selling contaminated fuel.

[GaryMayo]

You guys can argue over the proper names to call the stuff that grows (alive) in modern stored diesel fuel, stuff that bothered no one before they fixed what was not broken by reinventing diesel.

Fact is, if you purchase diesel fuel today, and store it, better have a plan to ward off big repair bills later once the growths show up all through your fuel system.

Sample bottle stored away? Who does that? Every trucker should do that, I know of none that do. I also doubt any vendor would sign your bottle, first off, it is against the law to store fuel in an unapproved container anywhere in the USA.

Any good auto parts store can sell you diesel adtive that kills the growths.

[noelex 77]

Buy the best fuel from a high turnover place
Sample the fuel for water and clarity before it goes in
Filter the fuel before it goes into the tank
Have a good quality primary fuel filter
Have a fuel polishing system
Use a biocide
Have a fuel tank with an inspection hatch and clean if necessary
Make sure your filer cap cannot leak water

Unfortunatly you need to do most if not all the steps above these days. Diesel bug problems are becoming very common.

To answer the OP question. I would fit a fuel polishing system. It's major job is to keep the tank clean and water free, preventing problems. Now that the tank is clean is an ideal time to install one.

[GaryMayo]

Originally Posted by noelex 77

Buy the best fuel from a high turnover place
Sample the fuel for water and clarity before it goes in
Filter the fuel before it goes into the tank
Have a good quality primary fuel filter
Have a fuel polishing system
Use a biocide
Have a fuel tank with an inspection hatch and clean if necessary
Make sure your filer cap cannot leak water

Unfortunatly you need to do most if not all the steps above these days. Diesel bug problems are becoming very common.

To answer the OP question. I would fit a fuel polishing system. It's major job is to keep the tank clean and water free, preventing problems. Now that the tank is clean is an ideal time to install one.

Very good post!

Amazon.com: BioGuard Diesel Fuel Microbiocide/Additive 16oz.: Automotive

[Delancey]

so....everyone agrees I should install a multi-stage fuel filtering set-up something like 30/10/2 micron before the lift pump?

As before the engine itself is a 28 year old Universal M-50 (5444) which is based on a Kubota block. The manual that came with the boat doesn't indicate what micron size the fuel should be filtered to but as an older engine I am going to guess the 10 Micron filter installed on the engine is what is required.

That said, I like the idea of filtering down to 2 micron even though some may think this is a waste. Some may also think multi stage filtering is a waste but it makes perfect sense to me. Thanks DeepFrz for the link to the Seaboard Marine article, interesting reading.

Having a parallel filter set-up sounds like a good idea but I am wondering if a really effective multistage filtering doesn't obviate the need for it? Same goes for "fuel polishing"?

I am mean, constantly re-filtering your fuel to keep it clean so it can just sit there in the tank until it is called to the engine where it gets filtered again? Isn't that a waste? Why not have bad-assed oversized (surface area) filters and do it once, when it's on it's way the engine?

[gettinthere]

Your idea of one single 3 part filtering system has one major flaw. If you take on a bad load of fuel, the first filter in the system will clog and you will be dead in the water.

That is what the twin filter system is for. If one of the primary filters clogs, you can switch over to the other primary while changing the clogged one.

I have a polishing system. Every time I take on fuel, I polish it. If I haven't polished in a while, I run it. It's CHEAP insurance. So much easier to do this than to try to change filters while underway.
The polisher draws from the very bottom of the tank and returns fuel to the top of the tank.

[DeepFrz]

Delancy:

Having a parallel filter set-up sounds like a good idea but I am wondering if a really effective multistage filtering doesn't obviate the need for it? Same goes for "fuel polishing"?

Fuel polishing is a good idea, depending on the size of your tanks and how much fuel you use. If I had a long range trawler I would definitely have a fuel polishing system. If I had a 20 gal fuel tank in a small sailboat, I probably wouldn't. If I had 100 gals of fuel in tanks on board I would also have one. You decide where the cut off makes sense to you.

Gettinthere:

Your idea of one single 3 part filtering system has one major flaw. If you take on a bad load of fuel, the first filter in the system will clog and you will be dead in the water.

Not necessarily. The idea of multistage is that each filter takes out a share of the grunge. However, one of the filters might plug up first. Using a vacuum gauge should give you warning of this. If you take on really horrible fuel then you aren't paying enough attention during the refueling operation.

[Delancey]

A comment from a different thread has got me thinking. I recently installed inspection ports as a part of my tank cleaning project. The ports allowed me to do a thorough inspection of the interior surfaces.

I found some fairly minor pitting across the bottom of the tank, not enough for me to worry about replacing the tank anytime soon, so I didn't think much about it at the time.

Fast forward to cleaning out the screen filter in my lift pump. I found a substantial amount of rusty crud attached to a magnet inside the pump. As the tank itself is aluminum, the rusty crud presumably came from fuel itself wherever the PO sourced his fuel.

Put two and two together and I am thinking the rusty crud is the culprit responsible for the pitting I found on the bottom of the tank. If you have aluminum tanks, I think this might be just one reason to pre-filter your fuel.