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Lodesman · 28-12-2009, 07:02

Quote:

Originally Posted by mesquaukee

A acquaintance of mine on a 65 foot trawler once every 5 years or so goes to Venezuela and fills up with 8,000 gallons of diesel. He adds 100 gallons of gasoline to it. Then he comes back to Panama and Columbia and cruises for 5 years on it.
Never uses biocide, he says the gasoline kills it. He used to be a professional fisherman.

I know the gasoline won't hurt the engine, but I would be concerned that the gasoline would vapourize and present an explosion hazard. One of the reasons we use diesel, is it's safer on a boat than gasoline.

eyschulman · 02-02-2010, 18:24

Just polishing the fuel from a badly contaminated tank may be a wast of time-the tank has to be opened inspected scrubed and fully cleaned-if tank has no inspection port time to install same-now you can put the scrubbed fuel back in with a loading dose of antibiotic additive. Why? the crud sticks to side of tank and will start growth again or if biocide used start falling of and plug up works again. Some comercial fishing boats don't mess with the idea of clean tanks they install multi stage bulk primary spin on filtration systems and buy the filters in large quantity.

eyschulman · 09-02-2010, 16:00

fuel polishing will clean the fuel but not likely to clean a dirty tank-the biojunk-gunk sticks to sides and bottom and if you polish the left over stuff is like a starter to begin the whole contamination process again. If you have an inspection port a thourough tank cleaning before refueling with clean fuel with bioside agent is probably best solution. Ports can be added to tanks I believe that kits are available(don't have details on that). Some comercial boats don't even bother with tank they have large spin on high capacity bulk filters ( buy elements by the dozen) in fuel line before the other filters some times called a multi stage system. When bulk filter clogs they switch to bypass and screw a new one on without missing a beat.

Charlie · 09-02-2010, 16:28

Quote:

Originally Posted by sundown

Thanks everyone for the suggestions of how to fix the fuel problem: There doesn't appear to be a working fuel polisher within 100 kms of where I live either for rent or for hire. I am seriously thinking about building one and renting the darn thing out!

Dealing with the actual fuel should be manageable but I am not too sure what to flush the tanks with? I will do a 'search' and see what I can come up with - I have put biocide in the tanks (closing the barn after the horse has run out). I am sure that there will be a bunch of sludge to deal with. Ah well - monkey wrenching is half the fun of owning a boat.

I had fuel problems like that and what I ended up doing was cutting access holes in my fuel tanks and scrubbing the tanks out with windex and scotch brite pads. The tanks look good as new now. It was a pain in the ass but I had the tanks polished and a year later one of the tanks scraped all of the crud from the sides in a rough sea.

I know the tanks are clean b/c my son filled the fuel tank with water and I had to empty out the tank last month. When I opened the access ports the tanks were clean as a whistle.

Melling · 18-10-2010, 20:05

Stop thinking bugs and instead think about oxidation and other form of degradation and contamination. Algae X, Biobor etc are usually a waste of time and money because the black stuff is asphaltene which is a black sludge. Google asphaltene and read the scientific literature. Valvtech or any good stabilizer works. Top marinas sell diesel with Valvtech in it. I installed a low flow and low pressure pollisher which uses the fuel return lines. The engines must be off when it is run to avoid getting air in the lines. My fuel problems have ended when I stopped thinking bugs and trying to avoid condensation. Also I had very little water in the system when I drew from the sumps and tapped the Racors.
Steve d'Antonio has written much on the subject for Passage.Maker magazine.

BTW, degradation of diesel is a problem in the tropics more than the North. I live in Minnesota where algae and asphaltene are never mentioned.

kathrine33 · 19-10-2010, 12:29

I want to buy some jugs for deisel.
do you know which are good????

Talbot · 19-10-2010, 12:33

Quote:

Originally Posted by kathrine33

I want to buy some jugs for deisel.
do you know which are good????

Worth looking at military grade uncrushable polyethylene 5l fuel cans such as Limes offers plastic fuel jerry cans and military plastic fuel jerry cans holders

Julie Mor · 22-12-2014, 12:08

I realize this thread is five years old but its information is timeless.

We've been looking at boats and some have been sitting a year or more without any use. The fuel is that old or older and who knows what the inside of the tank looks like.

Just one more thing that needs to be addressed when buying a boat. Thanks go out to all who contributed to this thread.

DeepFrz · 22-12-2014, 13:09

Quote:

Stop thinking bugs and instead think about oxidation and other form of degradation and contamination. Algae X, Biobor etc are usually a waste of time and money because the black stuff is asphaltene which is a black sludge. Google asphaltene and read the scientific literature. Valvtech or any good stabilizer works. Top marinas sell diesel with Valvtech in it.

You can test if the deposits in your tank are asphaltene or biological contamination by a few drops of household bleach on a blob of the deposit. If it remains black it is asphaltene, if it changes to a whitish color it is biological deposits.

Xlantic · 12-01-2015, 14:50

I installed daytanks in my boat as that seemed to me to be the only reliable solution for my 30+ year old tanks.

The gunk (asphaltenes, biological debris or whatever its is) that accumulates over time in boat diesel tanks seems to stick to the walls of the tank and is released to clog the engine filters at the most inopportune times: in a seaway.

Multiple filters that can be switched over are are not always effective because the amount of gunk released can overwhelm not just the first filter but also the back-up.

Inspection ports are often not effective because the baffles limit the access for cleaning the inside of the tanks.

Fuel polishing can help but it is not going to remove the sludge sticking to the walls, bottom and baffles of the tank.

I question biocides that attribute the problem to algae as no algae is going to grow inside a dark tank.

So, for me, the solution was to install daytanks that I fill up with filtered fuel on a daily basis when cruising. (I also have a permanent fuel polishing system that I run while cruising when the motion of the boat shakes-up the crud in the tanks.)

MarkSF · 12-01-2015, 15:05

Quote:

Originally Posted by r.furborough

On the contrary, gasoline used to be added to diesel fuel during the winter months by truck dirvers to prevent waxing, it used to be common practice and if used in moderation caused no engine damage.

Maybe that used to be the case, but not any more. Modern diesels use very high pressure pumps. The lubricity of modern ultra-low-sulphur diesel is marginal for these pumps, even when un-diluted. If you add gasoline to it, you could lower the lubricity below an acceptable threshold and cause severe, and incredibly expensive, damage to the fuel system.

In fact there has been discussion on the sailing forums of the marginal lubricity of modern ULSD, and the need for additives to increase lubricity, even on older engines with much lower pressure fuel pumps.

On the latest generation of "clean diesels", in the event of fuel pump failure, VW has taken to testing the fuel for any gasoline, and will deny your warranty claim if any is present. The repair cost is about $7000.

If you want to add something to diesel, how about one of the excellent additives designed for the job?