Cleaning a fuel tank - top tips?

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This season's big cruise saw the the engine stop due to a dirty filter. On blowing down into the tank and siphoning back up there was evidence of lots of dirt, recently disturbed by a rough passage, but no evidence of fuel bug (nothing too dark, sticky and viscous).

So, now returned, I'm facing cleaning out the fuel tank. It's on a 1980 Moody 33 - the original tank, with a circular access opening on top about 1ft across, through which the fuel guage also goes. The tank is about 2-3ft deep. Will also be interested in the extent of any rusting, although none is obvious.

Apart from elbow grease - are there any top tips on cleaning agents, methods, and disposal of old diesel in the Gosport area?

Any help greatly appreciated...

Nick
 
I cleaned my 12 gallon tank (which doesn't have an access hole) using a steam wallpaper stripping machine. I removed the tank from the boat and connected the stripper hose to it. I let it steam with the tank in different positions until no more dirty water came out. It took about 3 days, using the machine during daylight hours.
 
As Parsifal says, steam cleaning with the tank removed from the boat has to be the best method, one of the few that will remove all traces of bug if any is present. Taking it to a motor garage and getting them to steam it out would be faster and not too expensive.

If this is not an option a Pela or small vacuum pump can reach into corners but cannot cope with large debris, such as rust flakes. Drain down the diesel and use paraffin for the cleaning, its lower viscosity makes it far more effective. Agitating it with a drill-driven stirrer will help to dislodge any caked-on debris.
 
If it's just fairly inert dirt you need to remove, the pela with a bigger bore hose is quite effective.
Just keep sucking from around the bottom of the tank until you can only find clean diesel.
Collect lots of plastic milk bottles, let the diesel settle for a day or two then 95% of it can be returned to the tank, via a sieve or a filter. Be warned, the modern foil sealed milk pots don't seal that well, so carry them wedged upright in a stack'n'store box....
The remainder can be left to settle again until you are left with some grot that goes in a waste oil bin.
I believe the household waste facility at PortSolent is shut at the moment, that's where I normally go with waste oil.
 
Apart from elbow grease - are there any top tips on cleaning agents, methods, and disposal of old diesel in the Gosport area?

Any help greatly appreciated...

Nick[/QUOTE]

It's one of two strategies - total clean taking considerable time and effort (as others have explained) or the 80:20 solution using your access panel to remove debris in situ, having drained down the bulk of the fuel for reuse. If no bug present the latter is recommended - if you suspect infection, it's the steam cleaner route - in situ or out.

Check visually for rust in the - use one of those bendy spined mirrors for a good gander.
Rust means complete refirb or even tank replacement - ouch!

Good luck!

PWG
 
Sorry if this is hijacking the thread, but I wonder if we may address another scenario? My boat has a glassed in GRP tank (100 litre) with an inspection panel on the side. Obviously I can't remove the tank for cleaning so must drain it, remove the panel and clean it out manually from the side - shudder! But what do I use to reseal the panel with? It appears to have been undistrubed for the last 23 years, attached with self tappers and sealed with a black, non-setting sealant. As the boat doesn't suffer from nasty niffs, I'm reluctant to start the job until I'm sure I have an effective sealant to prevent leakage into the bilges.

Rob.
 
I had a Moody with the same sort of tank. It was quite easy to clean effectively as follows:

1/ empty the tank - put the dirty diesel into 5 gall containers, dose the diesel with bug killer and put the containers to stand in the shed. You can re-use that diesel by syphoning off the clean stuff after a couple of months to give the dea bugs etc time to settle to the bottom.

2. pour gunk into the tank and with a long stick / mop, rub the sides of the tank with gunk. Preferably the old style gunk which was like jeyes fluid

3/ wash out with water using the pressure washer to make sure all the goo on the inside has been removed

4 repeat the washing using either more gunk or a detergent. do this twice.

4/ empty the tank and dry it inside ( cloths, paper towels, hot airl dryer)

The boat concerned is still in the club and 5 years later has had no repeat infection.
 
I just had to replace the fuel tank on my 20 year old Moody 31 Mk 2. There was a fair bit of cosmetic rust on the outside - but the tank had rusted from the INSIDE with clean metal on the outside in the region of the pin-holes. The rust was at the bottom of the tank, presumably in an area where water in the diesel had accumulated. If you've got an accumulation of debris inside the tank and it isn't diesel bug, then I'd suspect something similar is happening to you.

A plug for West of Scotland Engineering (www.wose.co.uk) who fabricated a new tank in three days, and made it so accurately that the existing mounting holed could be used - we were all certain we'd have to re-drill at least one! No connection; a pleased customer. The price was sensible, I am informed by engineering friends.

Hopefully I've got 20 years before I need to worry again! As two of the mounting bolts are inaccessible from the rear, getting the old tank out and the new one in was a bit of an adventure. But I now know the fuel system on Capricious from one end to the other.
 
Thanks everyone for your replies. I look forward to the endeavour in some respects. Getting the tank out will not be easy, so I will try the in situ methods first!

Nick
 
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