I recently had to sort out a tank full of diesel buggy fuel.
The symptoms only became apparent after a rough Irish Sea crossing in June when the engine cut out. We (a friend and I) put it down to an air lock. we fixed it quickly by re-priming the engine.
Then as the engine cut out again, several hours of motoring and days later, we put it down to water still making its way out.
When it cut out again, I suspected something else.
When it cut out again, I went through the entire fuel system and discovered that in the space of 10 days, my entire fuel tank had turned to opaque pineapple juice.
I've only ever used white diesel, given that I only use about half a tank of fuel a year, the cost is negligible. (145 ltr tank)
I now realise that it's equally, if not more prone to the bug as red diesel due to the element of bio that's added these days by the manufacturer. Marine 16 is now my friend. (other brands of biocide are available)
You can see what it looked like via my blog post and the steps I took to sort it out. I would have done some research to find Australian diesel polishers, but as I can't vouch for them personally and that would be advertising, I've avoided doing that. Otherwise, the images show what dirty diesel can look like and what catching it early, also looks like in terms of fuel tank deposits.
I've included a "diesel" joke because, well, just because. :-)
www.boogie-nights.org/2016/08/diesel-fitter.html
Thanks for the write up. I had a similar problem recently and the only cure is to clean the tank and start over with fresh fuel and filters. In Australia we only have road diesel available these days, the heavy diesels are long gone. There used to be bio diesel available from the pumps but this disappeared when the government took away the subsidies. I doubt whether anyone polishes diesel in this country either. In my case the tank only holds 40 litres so it costs very little to dump this fuel onto my mate and just buy fresh stuff. I thought about building a polishing set up but really the odd occasion I used it would not warrant the expenditure and I'm inherently lazy.
One problem that sometimes occurs with diesel in Western Australia is "Waxing". Most of our diesel supplied to WA is a summer formula so when we are subjected to frosts and cold snaps the diesel starts trying to solidify and clogs up the fueling systems, it simply wont pump. If we sustain a max temperature of aprox 12 deg C during the the day and the temperature drops below 0 deg C over night, sometimes it wont even pump from the bowser . You've just got to let it warm up.
Unfortunately when this happens there is sometimes a wave of panic, out come the spanners and the local mechanics phone is running hot. This may never be a problem in a boat if you stay local but if you where to take on fuel here and head off to a colder climate you may have real trouble.
Keep up the good work Misfit 
Thanks for sharing Misfit. In Aus there is a company that produces and distributes a number of additives for diesel fuel and engine oil.
On Ramona's recommendation I bought and use their FTC decarboniser fuel additive. It seems to be working well.
Link to Cost Effective Maintenance:- costeffective.com.au/product/ftc-decarbonizer/
The following has to be one of the best reads on diesel fuel system cleanliness I have read, the bloke talks sense and says it in a style that laymen can understand. If people were to adopt his logic and approach I think most people's fuel problems would be a non event.
www.trawlersandtrawlering.com/howto/captnwil.html
Reading the article LooseChange posted would there be any benefit to install a ball valve in the fuel tank vent line that could be closed when not in use to prevent moist air from entering the tank? In lieu of the desiccant filter as stated in the article, copied below;
There are two ways to prevent condensation on the (inside) surface of the tank ;
(1) Raise the temperature of the surface above the dew point of the air or
(2) Reduce the dew point of the air below the temperature of the surface.
Desiccant filters can also be made to work like the second case. Desiccant filters in the vent lines have tremendous possibilities. If they can be fitted properly, they will keep most of the moisture in the air from entering the fuel tank, which will lower the dew point of the air to very low levels.
Select to expand quoteseabird said..
Reading the article LooseChange posted would there be any benefit to install a ball valve in the fuel tank vent line that could be closed when not in use to prevent moist air from entering the tank? In lieu of the desiccant filter as stated in the article, copied below;
There are two ways to prevent condensation on the (inside) surface of the tank ;
(1) Raise the temperature of the surface above the dew point of the air or
(2) Reduce the dew point of the air below the temperature of the surface.
Desiccant filters can also be made to work like the second case. Desiccant filters in the vent lines have tremendous possibilities. If they can be fitted properly, they will keep most of the moisture in the air from entering the fuel tank, which will lower the dew point of the air to very low levels.
There is another way- insulate the tank. This stabilises the temperature of the fuel and tank, and makes it less likely to "breathe" as it heats and cools.
One to watch out for is an Oz product called "Fueltreat". It is strictly a biocide (kills bugs) not an emulsifier/dispersant (these spread the water into suspension in tiny bits so the bugs can't build a metropolis, and might also have a little biocide).
I used it for a few years, and for bigger engines with sizable outlets and a fairly high rate of fuel turnover I'm sure it is great. After all, it is distributed by Caterpillar.
But I found that even at the recommended dose, a gooey residue would build up that sank to the bottom and was viscous enough to clog the stupidly tiny outlet on my tank. So I switched to the Chemtech diesel treatment from WW's about 18 months ago. Same conditions (Melbourne winters, not always full, high residence time due to low usage, $^%&ing tiny tank outlet) and have no bugs, no problem at all.
I did pull, vacuum, rinse and sterilize the tank (with metho) before the switch.
Yes, I should pull the tank and fix it properly: it's somewhere on the list of 1,000,000 jobs for my 40-yo Compass!
Cheers, Graeme
Select to expand quoteYara said..seabird said..
Reading the article LooseChange posted would there be any benefit to install a ball valve in the fuel tank vent line that could be closed when not in use to prevent moist air from entering the tank? In lieu of the desiccant filter as stated in the article, copied below;
There are two ways to prevent condensation on the (inside) surface of the tank ;
(1) Raise the temperature of the surface above the dew point of the air or
(2) Reduce the dew point of the air below the temperature of the surface.
Desiccant filters can also be made to work like the second case. Desiccant filters in the vent lines have tremendous possibilities. If they can be fitted properly, they will keep most of the moisture in the air from entering the fuel tank, which will lower the dew point of the air to very low levels.
There is another way- insulate the tank. This stabilises the temperature of the fuel and tank, and makes it less likely to "breathe" as it heats and cools.
Most yachts would have there fuel tanks low down, usually in the space above the lead keel so the temperature would only vary really with the sea water temperature. Flat bottom modern boats it's just another handicap. The capacity of the tank is probably the best way to keep the fuel contaminate free. There is no need to carry more than 40 litres and if your going to be absent from your vessel for some time leave the tank full.
The problem I have is the SS tank is 100lts which is way too large for my usage which is day/ weekend trips. So I only ever half fill.
My tank is located in a locker accessed from the cockpit with the filler cap on the cockpit floor.
Every time I open the filler cap there is condensation on the underside of the cap.
I think insulation will help reduce the build up of water in the tank and will be fairly easy to install.
I had diesel bug (white stuff and water) big time when I bought old unused Martzcraft 35. 200L diesel tank.
I bought a 12V fuel pump from Supa Cheap Autos for $50 and two CAV fuel filters $50 each (cant remember exactly).
Then I put the fuel pump and two filters in series and sucked the fuel out of the tank bottom and poured the clean result into the tank top and left the loop going going going. We sailed around a day heeling as much as possible to stir up the tank.
After a couple of days the fuel was clear and problem gone.
Then...embarrassing... I lent the boat to a friend for the weekend and he put petrol in it not diesel!!! That required complete draining and refilling.
