Left diesel filler cap off and it has rained

Went to the boat today and encountered more problems. I couldn't shift the diesel filler pipe from the top of the tank nor from under the filler cap. The pipe is nearly three feet long so trying to drain a tank from the filler cap would be very difficult, assuming that I had a long enough tube. I managed to undo the tank breather tube but it is not wide enough to take the tube from my Pela. It would take the narrow tube which came with the Pela but that has long since gone.
The tank is translucent plastic and on examination the only part that is not pink, presumably diesel, is a small footing below the bottom and which is about 10cm*2cm*1cm. There is another protuberance below the tank which holds the diesel out tap, but I can't tell whether it has water in it or is opaque. I'd be surprised if there is more than 50 ml of water in the tank.
I'd like to get at the water, if any, at the bottom of the tank. Can anyone advise how I can remove the filler pipe from the tank without cutting it? Also does anyone sell Pela pump spares? I've googled the WEB but have had no luck so far.
 
On the tank I had problems with (steel) the best way to get a tube down to the bottom of the sump was to carefully remove the fuel gauge sender which allowed me to direct the suction tube down to the lowest point, care is needed in extracting the float and in making a good seal when you replace it. Like you I found that the filler pipe was too short straight and stiff to come out other than by cutting it but it was at the other end of the tank from the sump anyway. You could try the idea of fishing with the hygroscopic crystals in a weighted cloth bag on a string, with your translucent tank you should be able to watch if it gets to the bottom. The water is unlikely ever to get into your system as the feed pipe is usually well above the bottom, but if you do not take the water out you have created the conditions for diesel bug and while you can poison that with a biocide like Grotamar you are better to try and maintain a clean tank if possible. 50ml. is enough water to get the bug going at the interface with the fuel.
There are chemists on here who could tell you what to use if you wanted to DIY the bag idea.
 
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Found Craythorne & de Tessier who sell spare Pela tubes. Unfortunately their WEB site keeps on trying to charge me double. I will te1elephone them tomorrow.
 
I dont know how many times and for how long the rain was potentially contaminating your fuel, but the amount actually adsorbed by the tank will be quite small assuming that you have a 2 inch filler pipe. I would suspect at worse it will be a couple of hundred millilitres. The water will lie at the bottom of the tank, and so should be accessible with a Pela or similar. After that your inline water trap should get the rest, as the flow rate through it will be quite slow, as long as you empty it regularly.
Unfortunately water is the catalyst for diesel bug, as the beasties grow in the water oil interface
 
Still awaiting the replacement Pela tube, so have yet to pump draw off water at bottom of tank. I've been googling "Soltron" and came across "Fuel Doctor" which claims to remove water at bottom of a tank. Has anyone used it and does it work?
 
In the end I drained off all the diesel and replaced it with fifteen litres of fresh diesel. Although I could not see any sign of water through the translucent tank, I added a good dose of Fuel Doctor.

The yacht is now out of the water for the winter, having motored only about 10 miles without any problems since the replacing the diesel. While "winterising" the engine, I decided to inspect the Perkins water filter. On undoing the drain plug, I extracted about a small cupful of a dark chocolate liquid which I take is discoloured diesel. There is probably more of the liquid as I did not continue until it was clear diesel. I have not yet tipped the chocolate liquid into a clear container to see how it settles.

I would welcome advice on whether I have a problem, and whether I should continue to drain off the chocolate liquid. Also would I have to bleed the fuel system?
 
Bio contamination produces a brown jelly which passes around the fuel system when it's not conjealed in the bottom of the tank. This is why you have to flush the whole system and change the filters when you get it (the bug that is) or the overflow from the injectors will just re-contaminate the tank. Whatever's in your sight glass didn't ought to be brown, guv.....
 
The "black coffee" drawn off from the water filter does not contain any water. Some coffee colour sediment was left behind when I decanted the diesel mixture into a jamjar. I telephoned Essolube, the supplier of Fuel Doctor. They think that it is most likely sludge disturbed when I rplaced he old diesel. They recommend that I dump the contaminated diesel and fill up the 30L tank with fresh diesel and dose it again with Fuel Doctor. What worries me about this, is that I might end up with a tank full of contaminated diesel.

As the yacht is now out of the water, I think that I will bite the bullet and have another look at whether I can get the tank out of the cockpit locker and give it a clean. From a previous inspection, one problem will be removing the filler pipe to the tank which I could not shift. I might have to saw through the pipe and replace. I can't see how I can clean completely drain the tank in situ. any other ideas, please?
 
pvb said:
Gosh, that sounds like a lot of work. If you've dosed the fuel, and if you have a primary filter, why bother?
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Agree! I got sludge in bottom of tank. To save the diesel, about 17 gallons, I bought a dustbin and pumped the tank nearly dry from the top into the dustbin. I cleaned the bottom of the tank, as best I could from the top with rags soaked in paraffin, firmly attached(!) through the filler pipe, trying to make sure I wiped most of the floor of the tank. Took about an hour. Unfortunately I could not reach a section beyond a baffle. Then filtered the diesel as I put it back in the tank and added Starbrite potion. So far so good, despite lots of bouncing about in this season's rough seas and strong winds.
 
Miker said:
Thanks everyone for the welcome advice. I've decided to draw off the diesel from the top of the tank using my oil exractor pump. I agree that it is not worth the hassle of decanting the diesel for a saving of £25, and have obtained an old 20 litre oil drum from the local garage to take the diesel to the tip. I have some diesel bug additive on the boat but don't yet know whether it is a suitable water absorber.
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And you will probably leave the water sitting on the bottom of the tank waiting for a blanket of clean fresh fuel to pollute.:D:D

Absolutely no need to draw fuel from the top....Just suck out the water from the bottom. You can improve the job by getting mates around to stand in appropriate places on the boat so that it is trimmed to put the deepest part of the tank under the Pela Hose. This will ensure removing the MAX water.

If sucking from STB side of tank stand on starboard side. If Starb aft then all stand aft if starb forard then all stand forard. It sounds like just a wee boat.

Vice versa for port.
 
Rainfall is measured in inches. 1/2 inch of rain in one event is considered a good downfall, 1inch often produces local flooding. Back to your boat, if 1" fell that would be 84 gallons over the surface area of the boat. If all of it drained into your tank, that would be a serious problem. In practice, you could realistically assume that most of it would drain overboard as the fuel filler usually stands proud of the deck by about 5mm. It depends on the layout of the deck/skuppers/drains etc. You could, after ensuring your filler cap is securely screwed on, try sluicing a bucket of water along the deck and estimating how much would have gone down the hole.
If your tank has a bottom drainoff point, I would draw off a few litres and check visually for water. If none or little - you do not have a problem. If you have no bottom drain, try drawing a sample off your primary filter - again this will give you an indication of fuel in the tank. Drw off by either route until no water appears.
 
Thanks everyone. The problem has moved on. I don't think that there is now any water in the tank, if there ever was. It is the sludge that I have stirred up in emptying and refilling the tank.
 
Thanks again everyone for the welcome advice. I think now that I have been barking up the wrong tree. I went to the boat today and drew off a litre of diesel from the top and a litre from the bottom of the tank. The diesel was clear with no sign of sludge. When I returned home, I added water to the small pickle jar's worth of black coffee coloured liquid drawn off from the water filter. So far, after two hours there is no sign of water separation, so I take it that what I had drawn off was water and crud, not diesel as I thought. With hindsight, I should have done this earlier as advised.

Where to now? I will continue to draw off water from the Perkins filter until clean diesel flows out. I have winterised the engine, and before I put the boat back in the water, I will change the fuel filter. Should I do this now and, perhaps, run the engine for a minute or two with no raw water circulating?
 
Take the top off the seacock, close the valve and put a hose into it, run the engine as long as you need to. Over the winter you will probably get condecension in the tank anyway, so new filters next spring, and renew after the first few hours, watching the water separator carefully.
Don't panic about this, diesel fuel is never clean these days. Its all down to the filters, and can you change them if caught out.

I took out 800 litres, cleaned the tank, put the fuel back, and the sedimenter turned completely black. Obviously I had disturbed the sediment and not picked it all up. For the next few weeks I was changing filters, initally after the first hour, then 12 hours and so on until it all came clean. Recommend Fuel Set.http://www.liquideng.co.uk/
 
Went to the boat again and drew off more water/crud from the Perkins primary water filter until clean diesel came out. In all, I have drawn off about half the capacity of the filter before I got to the clean diesel. I have to add a few more litres to the tank to top it up but I reckon that I can leave changing the fuel filter until relaunch next Spring.
However, it has turned me into a nervous wreck! As I had added some diesel, I checked that I had replaced the filler cap at least twice before leaving the boat.
 
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