john m
Well-Known Member
the diesel in my tank has been lying for about 3 years although the engine runs and starts should i drain and replace befor launching or can i buy something to freshen it up
should i drain diesel tank
- Thread starter john m
- Start date
Adamastor
Well-Known Member
diesel biocide and a few new filters? Rather than waste the diesel? Got a diesel-heater- maybe you could use it in that instead? Biocide and I aren't good mates- I've had to suck bio-slime from fuel-lines more than once after inocculating the tank!
Evadne
Well-Known Member
If you've a drain at the bottom of the tank then just drain off the lower 100cc of water and slime before starting. It'll save your filters as well.
Relax
Well-Known Member
Personally I'd drain as much off the tank as it takes to get the diesel to come clean.
I just had to do this to mine and its incredible the crap that comes out - and yes my engine was running fine too!!
I had to syphon off about 15 litres from the bottom of the tank until I got rid of the gunk and water (particularly) - I syphoned this (boat on the hard) a jam jar at a time so that I could see the contents clearly. I used some spare 10mm soft copper pipe with a washing machine valve at the end to syphon right from the bottom of hte tank.
I just had to do this to mine and its incredible the crap that comes out - and yes my engine was running fine too!!
I had to syphon off about 15 litres from the bottom of the tank until I got rid of the gunk and water (particularly) - I syphoned this (boat on the hard) a jam jar at a time so that I could see the contents clearly. I used some spare 10mm soft copper pipe with a washing machine valve at the end to syphon right from the bottom of hte tank.
fisherman
Well-Known Member
I have a 1000 litre tank, and last season started to get problems with the filters bunging up at less than the usual 200 hour interval. The local engineers say, as do others, that diesel is not the quality it was, more tars and asphalts etc in it, I need to change filters more, and why not deal with the root of the problem and clean the tank. So emptied it, took the plates off, the muck was stuck to the walls, I scraped it down, mopped it out, but could not get to the whole tank due to the baffles.
Put back the fuel, 700 litres, and the pre-filter sediment trap turned black. I can only supppose that the residual muck in the tank dried out while it was empty, or the fuel treatment has made it very mobile. It is too fine to drop into the tank sump. I'm draining the pre-filter every day, and changing engine filters after every 20-30 hours, using a Crosland 522 followed by a Delphi 296, after which there is clean fuel. Being a Ford, much more fuel is going through the filters than is used, so there is an improvement. Was it worth cleaning the tank? Not too sure, got more trouble now than before, but I'm hoping it will be much better when the tank is used up.
If not, I shall get a 24 volt pump, set of filters and a day tank, which would also be useful for an emergency supply, filled from the spare fuel I carry in cans.
Put back the fuel, 700 litres, and the pre-filter sediment trap turned black. I can only supppose that the residual muck in the tank dried out while it was empty, or the fuel treatment has made it very mobile. It is too fine to drop into the tank sump. I'm draining the pre-filter every day, and changing engine filters after every 20-30 hours, using a Crosland 522 followed by a Delphi 296, after which there is clean fuel. Being a Ford, much more fuel is going through the filters than is used, so there is an improvement. Was it worth cleaning the tank? Not too sure, got more trouble now than before, but I'm hoping it will be much better when the tank is used up.
If not, I shall get a 24 volt pump, set of filters and a day tank, which would also be useful for an emergency supply, filled from the spare fuel I carry in cans.
fisherman
Well-Known Member
[ QUOTE ]
- I syphoned this (boat on the hard) a jam jar at a time so that I could see the contents clearly. I used some spare 10mm soft copper pipe with a washing machine valve at the end to syphon right from the bottom of hte tank.
[/ QUOTE ]
You can buy a length of polythene pipe with a small foot valve for about £3. I used a piece of 1 inch hose with a big foot valve that cost about £12, ball valve the other end, did 700 litres in about 20 minutes.
Trouble is, there's been a few thefts of heating oil round here, will I get sussed if they see the big syphon and the four 200 litre drums?
- I syphoned this (boat on the hard) a jam jar at a time so that I could see the contents clearly. I used some spare 10mm soft copper pipe with a washing machine valve at the end to syphon right from the bottom of hte tank.
[/ QUOTE ]
You can buy a length of polythene pipe with a small foot valve for about £3. I used a piece of 1 inch hose with a big foot valve that cost about £12, ball valve the other end, did 700 litres in about 20 minutes.
Trouble is, there's been a few thefts of heating oil round here, will I get sussed if they see the big syphon and the four 200 litre drums?
TonyS
Well-Known Member
I recently had water in the filter. The first time after 5 years. Following advice from here I used the Pela oil vacuum extraction kit and put the end in the bottom corner of the tank by loosening the fuel level gauge. I discarded about 10l of fuel but the water and dirty fuel only accounted for about 1 litre. The fuel intake must be down there in the bottom corner of the tank! It is a stupid position for the fuel offtake. Why don't they make an offtake that takes diesel from just below the surface that floats down with the level in the tank?
William_H
Well-Known Member
High Tony the fuel take off on a floating boom is the system used for large fixed fuel installations and has merit. However it is only good if you regularly drain fuel from the lowest point to remove water and the other stuff. However there may be less benefit in a tank in motion. Rough water. Eventually if you use all your fuel you can be down to the dregs anyway.
I think the aviation standard for tank design is perhaps the best arrangement. This requires a small deep sump a the bottom of the tank which has a drain at the bottom. This is the water drain and should contain .5% or more of total tank capacity that can not be sucked up by the engine.
The engine pick up is just above this .5% point.
The ideal shape for a tank is conical shaped or deep vee so water etc goes into the bottom to be collected. If as in aircraft tank in wings you must have a wide low tank then you have to consider the fact that fuel may not be available at all times due to pitching and rolling when you get low. You end up with a larger amount of what is called unusable fuel. Which is that amount you can't be sure of being available. If this is a problem you need a header tank and extra pump so air can be sucked from the tank without problems.
Anyway that is just waffle. The answer to the original post is to suck off from the lowest point as much fuel as seems necessary to remove water and sludge. This should be done after the fuel has settled for 24hrs (no agitation). In fuel supply installations for aircaft this should be done daily. It may be beneficial if the boat tank has a flat bottom to heel the boat so one corner is lowest. Again ideally hold the boat heeled for as long as possible to get water and sludge to migrate to the lowest point.
Put fuel into a clear glass container and allow to settle so you can reuse the top clear fuel and discard the sludge etc. Beware If the container is all water you may think it clear fuel.
Incidentally because Jet fuel is usually almost the same as diesel (kerosene) they have similar problems of water and diesel bug. Aviation supply shops have water testing kits and biocides that may be usefull. olewill
I think the aviation standard for tank design is perhaps the best arrangement. This requires a small deep sump a the bottom of the tank which has a drain at the bottom. This is the water drain and should contain .5% or more of total tank capacity that can not be sucked up by the engine.
The engine pick up is just above this .5% point.
The ideal shape for a tank is conical shaped or deep vee so water etc goes into the bottom to be collected. If as in aircraft tank in wings you must have a wide low tank then you have to consider the fact that fuel may not be available at all times due to pitching and rolling when you get low. You end up with a larger amount of what is called unusable fuel. Which is that amount you can't be sure of being available. If this is a problem you need a header tank and extra pump so air can be sucked from the tank without problems.
Anyway that is just waffle. The answer to the original post is to suck off from the lowest point as much fuel as seems necessary to remove water and sludge. This should be done after the fuel has settled for 24hrs (no agitation). In fuel supply installations for aircaft this should be done daily. It may be beneficial if the boat tank has a flat bottom to heel the boat so one corner is lowest. Again ideally hold the boat heeled for as long as possible to get water and sludge to migrate to the lowest point.
Put fuel into a clear glass container and allow to settle so you can reuse the top clear fuel and discard the sludge etc. Beware If the container is all water you may think it clear fuel.
Incidentally because Jet fuel is usually almost the same as diesel (kerosene) they have similar problems of water and diesel bug. Aviation supply shops have water testing kits and biocides that may be usefull. olewill
sarabande
Well-Known Member
I think there's quite a difference between diesel and kerosene (which is more like paraffin)
Relax
Well-Known Member
There is very little difference between diesel and kerosine - the same specific gravity and the same calorific value. Diesel engines will run on kerosine.
Obviously there must be a chemical difference but not being a chemist........ /forums/images/graemlins/tongue.gif I don't know what that is. Maybe the lubricating value is different? Vic ????????????
Maybe I am over cautious but I have binned all fuel drawn off and thought to be contaminated. When you look at it in a jam jar there are often millions of tiny just-visible 'bits' floating even after the water has settled out. Better off my boat.
Obviously there must be a chemical difference but not being a chemist........ /forums/images/graemlins/tongue.gif I don't know what that is. Maybe the lubricating value is different? Vic ????????????
Maybe I am over cautious but I have binned all fuel drawn off and thought to be contaminated. When you look at it in a jam jar there are often millions of tiny just-visible 'bits' floating even after the water has settled out. Better off my boat.
Caer Urfa
Well-Known Member
I had the same problems.
Boat stood for two years before I bought her with full tanks of diesel.
Much to my surprise she ran fine for 18 months no problem then engine stopped dead 100 yards off some rocks!
Cutting a very long story short I finaly decided to remove both fuel tanks to clean them out fully, but had not planned on having to take half the boat apart to get them out.
Once out also re-piped the whole fuel system from Micro-bore to 3/8" bore and fitted totaly independant filter system to 'each tank'.
Loads of hard work but worth it in the end, by the way also used my pela pump to remove diesel from tanks, worked great!
Now 'I know 'my tanks are clean and not 'hopeing' they are clean.!
Boat stood for two years before I bought her with full tanks of diesel.
Much to my surprise she ran fine for 18 months no problem then engine stopped dead 100 yards off some rocks!
Cutting a very long story short I finaly decided to remove both fuel tanks to clean them out fully, but had not planned on having to take half the boat apart to get them out.
Once out also re-piped the whole fuel system from Micro-bore to 3/8" bore and fitted totaly independant filter system to 'each tank'.
Loads of hard work but worth it in the end, by the way also used my pela pump to remove diesel from tanks, worked great!
Now 'I know 'my tanks are clean and not 'hopeing' they are clean.!
bedouin
Well-Known Member
You can buy funnels that will filter out water and sediment from diesel.
I have one of these and on occasion I have drained my diesel tank, run all the contents through the filter, and refilled it. A "Pela" vacuum pump (as used for changing oil) is very good to suck up the last bit of the tank that won't drain through the take-off.
However should you feel the need to throw the contents of your tank away then please let me know and I will arrange for the safe recycling of your diesel, for a very modest sum /forums/images/graemlins/laugh.gif
I have one of these and on occasion I have drained my diesel tank, run all the contents through the filter, and refilled it. A "Pela" vacuum pump (as used for changing oil) is very good to suck up the last bit of the tank that won't drain through the take-off.
However should you feel the need to throw the contents of your tank away then please let me know and I will arrange for the safe recycling of your diesel, for a very modest sum /forums/images/graemlins/laugh.gif
morgandlm
Well-Known Member
Sorry, but this is simply not correct. Jet A1 (jet fuel) is exactly the same product as kerosene except that it does not contain any dye and is subject to a set of special handling storage conditions through the whole supply chain. Diesel fuel (gas Oil) has a significantly higher flash point than kerosene and is a different hydrocarbon fraction. It is however correct that they can both suffer from bugs when water is around.
Morgan
In 1945 when the RAF was taking some good examples of Me262s to Farnborough for evaluation, they flew them as far as the Channel coast on original fuel and then, because there was no other fuel available, filled them up with "...good quality diesel oil" for the cross channel leg.
