Fuel tank cleaning. My proposal.

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pcatterall

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I want to get my tanks and fuel clean for next season.
I have 2x 50 gallon tanks which are just connected by a pipe with a shut off valve.
There is only around 15 gallons in each tank at this time.
There is a large accessible inspection cover on each tank.
I propose to just scoop or pump out one tank into clear plastic containers ( the bottom couple of inches into a seperate container)
I will then clean and wipe out the empty tank.
When it is clean I will pour the settled fuel( after inspection) back in via a funnel with a fine mesh filter. ( I will take the containers home to let the fuel settle and decant as required)
I would then just repeat this on the other tank.
Clean water bowl change filters and ready to go! ??
Is this simple sounding process OK?
Any speciall tips on cleaning the tanks?
Anything I should do to to fuel before pouring back?
Should I add an anti bug treatment even if my fuel looks bug free?

Any other tips gratefully recieved
 
Filtering

Diesel bug is in effect invisible (except the results of its activity). So you will need to do something in addition to a fine mesh filter (which will only take out gross particles). Visual inspection cannot always reveal a bacterial infection.

I'd be inclined to rig up a two tank cleaning system ashore, with a header tank connected via a fine in-line diesel filter down to a receiver tank, and allow gravity to do the filtering for you.

Remove fuel from boat and add the bug killer; stir well and allow it to work.

Pour mixture into header tank and allow to flow gently, sweet Avon, through the filter into the receiver (tanks or cans) .

When it is all through, seal cans to prevent re-infection from atmosphere. Use to fill boat tanks when needed.



The shore based filter system is there for future use if needed.


Tank Cleaning

Much will depend on how the tanks are configured and how gunged up they are. As you have good access, then perhaps empty everything and go round with a long-handled brush and paraffin (or paraffin/petrol mixture), especially round the baffles and lower part of the tank. Flush a couple of times to ensure all traces of gunge are removed, then add cleaned diesel with bug killer as full as you can to avoid condensation over winter.

Perhaps it might be worth adding a separate delivery pipe from each tank via a primary filter to the fuel pump, so that you can isolate each tank at will.



Cheap inline physical filter

http://www.thornycroftparts.co.uk/I...Bio_Diesel_Petrol_Veg_WVO/p207754_422935.aspx


Fine fuel filters

http://www.dieselveg.com/fuel_filters.htm
 
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That's pretty much what I did 10 years ago and what I'm in the process of doing again this winter.
After 10 years the tanks are filthy again with a black sludge in the bottom which I guess is caused by the fuel bug. My understanding is that the black stuff is actually dead bacteria, in which case I shall treat the fuel I've removed, about 15 gallons, and allow the dead stuff to sink before I put the fuel back in the tank.
My biggest problem; for reasons that escape me whoever built my tanks put the inspection hatches on side and they are a bugger to reseal, they're steel tanks and have a rubber gasket which I'd like to replace with mastic, but so far, I've not found a mastic that will handle being immersed in diesel... any ideas ?
 
Ok, so we are going off the subject slightly but my fuel tanks also have side-access-hatches which do not seal well. How do you fit access hatches that seal properly when fuel is lopping against them?? Is there any gasket material that is fuel-proof?
 
pcatterall said:
Should I add an anti bug treatment even if my fuel looks bug free?
Click to expand...

Yes! Add a double dose of Startron or Soltron, and then continue to dose every time you add fuel.

Your cleaning technique sounds OK, my only concern would be that your tanks are almost certainly baffled, and cleaning around baffles isn't easy.

You will no doubt have residual bug rubbish in the system afterwards, so be prepared to change your primary fuel filter sooner rather than later.
 
Thanks all; helpful as always.
Thanks, Sarabande for the links. I had considered a seperate system for fuel delivery so that I could just 'switch' tanks in case of blocked filters etc. There seem to be some useful filter options in those links so I may go down that road.
Regarding the 'bug' I guess that I was assuming that if I couldn't see the 'effects of the bug then I would just treat against it.
Thanks again.
 
In regard to Diesel Bug, someone in this forum suggested to add small amount of petrol in the diesel as petrol is"poisonous"to diesel bugs. Any opinions or substantiations of this claim?
 
pjobson said:
Ok, so we are going off the subject slightly but my fuel tanks also have side-access-hatches which do not seal well. How do you fit access hatches that seal properly when fuel is lopping against them?? Is there any gasket material that is fuel-proof?
Click to expand...

Beldam Lascar Seals sell it, and mastic.
 
pjobson said:
Ok, so we are going off the subject slightly but my fuel tanks also have side-access-hatches which do not seal well. How do you fit access hatches that seal properly when fuel is lopping against them?? Is there any gasket material that is fuel-proof?
Click to expand...

I used to have a persistent diesel leak from a tank where the fuel gauge sender went through, there was also a large access plate which came off for cleaning out.
The inspection hatch and sender plate on my tank was on the top but since the tank was a very flat profile it was as vulnerable as yours as soon as the boat heeled. There was a neoprene gasket but the two overlapping surfaces were sheet steel and the cover was much thicker than the tank. I used generous coatings of non setting gasket cement, the old red stuff which worked, but these days I think I would go for Hylomar which is claimed to be resistant to all types of fuels. I used petrol on a clean rag to clean all the surfaces but be sure not to smoke and turn the cooker off.
 
Re cleaning your tank. Do not be tempted to use paper towel or similar to wipe down the surfaces. If required use a lint free cloth.
If you use paper there is a very high risk of tiny fibres that may be left behind reconstituting into a pellet which will get trapped in a bend or joint and cause a partial blockage.
Don't ask how I know this!
 
The fact that you have got good inspection hatches is good. If your tank is anything like mine was last year, I think you may have a problems with a greasy/waxy like brown coating on side and bottom of the tank.
I used a solvent based engine cleaner, with a paint brish on a stick to remove the grease like coating. I then washed the tank out, and then pumped it out...
Finally I flashed up the steam based wallpaper stripper, and then steamed the sides and the bottom of the tank, taking with it, another load of crud which the solvents engine cleaner had not shifted.
Finally ended up with a grotty puddle of crud, which was pumped out, and finally dried out with old towels.

Should be OK for next 10 years
 
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