Diesel - Use By Date ?

Rappey

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each breath brings in more moisture trapped in the air
How? My tank has a small breather that has usually got fuel in it as it gurgles like crazy when filling the tank. If the boat was stationary ashore then the fuel may move up and down the 2m length of breather but cant see how it could introduce lots of fresh air.
 

dunedin

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It is advisable to fill diesel tanks on layup, to deprive the potential diesel bug of the air required to grow. Since the tank were filled, it may mitigate the dire consequences. If possible, I'd set up a system whereby the fuel could be run through filters before returning to the tank, thus 'polishing' it. It should save you a lot of expensive wasted diesel, and it is a good system to have in the event of dirty new fuel. Diluting with new, as already suggested, would never hurt, so long as you've got storage for the extra volume.
Interestingly some opinion has now switched to better to leave tank low over the winter and fill with fresh diesel in the spring, with modern diesel specs.
I am personally no expert, but seen this from some people who are.
 

JumbleDuck

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It is true but don't forget that the diurnal temperature change does get help from at least two other factors that help an exchange of air between an unfilled tank and the outside air.
Go on then. Pressure changes are unlikely to be more than a few parts per thousand and over 20C a steel tank changes its volume by about 0.07%, so it's neither of these.
 

peter gibbs

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I purchased the yacht 2 years ago where it has since been stored in a barn.

I did see the engine run for 3 minutes before purchasing.

This boat hasn't floated for 4 years.

Full tank of diesel.

What to do ?
Answer- nothing.

My tank is stored full over winter, run to half emptyor so in the season and refilled for winter sgain. Just like most motor sailers. I guess there's fuel in there of some vintage but there are no noticeable consequences to using this mixture.

Nobody runs their tank to empty to be sure of using only fresh fuel.

You have no doubt replaced all filters on your engine. If all runs smoothly thereafter you saved yourself a lot of unnecessary work and cost.

PWG
 

Slowboat35

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I purchased the yacht 2 years ago where it has since been stored in a barn.

I did see the engine run for 3 minutes before purchasing.

This boat hasn't floated for 4 years.

Full tank of diesel.

What to do ?
Sample the fuel in the tank.
If the fuel sample is clear just use it.
If it isn't then polish it and then use it if there's enough to be bothered with or ditch it in the marina's waste oil container. Or keep it for lighting bonfires, degreasing, or mix it with old engine oil as a good creosote substitute.
 
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You could also add a huge dose of chilli powder to it, apparently it kills off critters. (-;
 

Dellquay13

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I took 4 gallons of old red out of my tank when i bought my boat, and put it in the yard oil bund. I thought i was refilling an empty tank with fresh diesel, but it turned out my pump hose had missed about 4 pints of sludgy water at the bottom of the tank, which stopped the motor on my delivery trip from the boatyard to the marina. luckily i had rigged my tender outboard up as an emergency backup.
It turned out rainwater had been getting in past a failed O ring on the filler cap, for the 2 years the previous owner had not used the boat.
 
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a) Buy a Refleks heater and use it in it. (Then go around telling everyone how they should throw out their year old diesel and offer to help them with it to run it the rest of the time).

b) Keep it in a big drum and use it as a parts cleaner/lubricator. It's pretty good as a penetrating oil, e.g. you can further mix with acetone for unseizing things. If, of course, you work on big, dirty engine stuffs.
 

Bilgediver

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I once delivered a yacht that had a huge full tank of diesel, that had been ashore unused about 10 years. But that was with old red diesel, not the nasty modern mucked-about-with biodiesel.

The problem used to be only due to a mixture of contaminated fuel and water . If the local storage tank got contaminated then it spread further. Unfortunately it seems this is now an inherent problem with bio fuel which may even determine the shelf life of these products.

One thing that can help is to try and remove the water that lies in the bottom of a fuel tank . Unfortunately the builders of even superyachts do not always but drains at the bottom of a fuel tank to help with this.

On some boats it is possible to lower a small bore pipe into the tank via the filler or some other aperture and then trim the boat so that the tank bottom below this access is the lowest point of the tank and then draw out the contents with a pump till clean oil appears. This water will often not be removed using a polishing system attached to the fuel system as it might be drawing from a higher level. If no such access is available to the tank then It should be possible on many boats to create a suitable access for this purpose to reach the lowest point of the tank.
 
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Blueboatman

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Design note :
Whilst I have a drain plug , it would be so much neater to have a drain spigot and shut off valve .
Job list No 286..?
 

Blueboatman

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Yup I’ve got that too, neat.
And the squeezy bulb doesn’t half save time ...
In fact I have the two relevant SPANNERS and a hanging torch clipped in the engine bay for the bleed on top of the primary , snd then the wee bleed atop the injector pump( Yanmar) .. after that, it self bleeds .. pretty much ?
But a shut off on the tank drain will be so nice
Once you take that drain plug out , whoosh ?
 
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