How to clean a fuel tank with no inspection hatch?

[lw395]

The problem is that to remove the crud you will have to give the walls of the tank a really good blast. Otherwise you will end up doing as above and simply making a couple of scrapes through it. Imagine trying to clean a filthy saucepan with a small tube through a hole? It really needs a scrub. I wonder if something could be done with a high pressure hose to blast the crud off the interior. You would need to undo all the pipes to allow the pressure out. You would either have to use diesel as the medium (I don't know if pressure washers can handle this) or you could use water and then use something to absorb the water residue once pumped out(I think acetone works). I don't think simply pumping it all out will really get the crud out as it will simply go to the bottom. This is why the hatch is the only practical option as you can get a hand in and literally scrub the tank. I completely replaced my old mild steel tank as it had crud, rust and no hatch. I now have a plastic job with hatch. No probs since.

I've seen some success with a length of old rope on the end of a sick poked into the tank then spun with a power drill on low speed.
On old motorbikes, it's common to put a few stones into a dirty oil tank and give it a good shake to stir things up.

In one sense, there is little point making your tank immaculate, you are only going to chuck greasy old diesel back in it.
What matters is getting rid of water, as the bug lives on the boundary between water and fuel mostly.

Pela the water out every six months, it's time well spent.

There will always be some crud, your filters must be able to cope with a sensible amount.

I can see a hatch might be worth cutting on an old problem taking that's been full of bad fuel and bug for years, or maybe one with a rough surface inside that crud sticks to.

 

[Chris_Robb]

Just found this on ASAPs site under Racor. Apparently the gauge substitutes for the T piece. Rather expensive though at over £100.
http://www.asap-supplies.com/search/racor+500/vacuum-gauge-for-racor-900-1000fh-series

I saw some suitable gauges on ebay (£6) but would I be able to get hold of the adaptor - any ideas ?
http://www.ebay.co.uk/itm/Vacuum-Ga...tion-253-/121140662940?_trksid=p2054897.l5658

Yes - or any other kind. The gauge isn't added to the filter, it goes between the filter and the lift pump.

I bought a brass T-piece like this:

Looking back through my email, the gauge scale was 0 to -1 bar, stated as being suitable for air, water or oil, and cost all of four quid

Pete

 

[prv]

Just found this on ASAPs site under Racor. Apparently the gauge substitutes for the T piece. Rather expensive though at over £100.

Also requires you to have massive motorboat-style filter housings, not the little spin-on cartridges we're talking about.

I saw some suitable gauges on ebay (£6) but would I be able to get hold of the adaptor - any ideas ?

What adaptor? You just need to tee it into the hose or pipe with some ordinary plumbing parts - read my earlier post. It's nothing to do with the filter head.

Pete

 

[Chris_Robb]

Also requires you to have massive motorboat-style filter housings, not the little spin-on cartridges we're talking about.


What adaptor? You just need to tee it into the hose or pipe with some ordinary plumbing parts - read my earlier post. It's nothing to do with the filter head.

Pete

I already have the Racor 500 unit on which this will fit. So a far easier option than re doing my feed pipe which is a single armoured hose from the filter to the engine. It seems so much easier just to replace the T piece on the top with the gauge. So all I need is the female to male adapter downsizing the threads.

 

[concentrik]

We had the same problem last year and as others have said, the only sure way is to cut an inspection hatch big enough to reach into. It's not that hard. We used a jigsaw, then cut a cover plate from sheet GRP, drilled securing holes round the edge of the cover, then fitted clinchnuts around the aperture to screw the cover plate on with. Cork gasket, no sealant.

It's worth noting that bug gloop can easily block the draw tube into the tank, starving the engine of fuel, even before any of the crud gets to the filters. Our filters were completely clean. We also fitted a vacuum gauge to the fuel line at the engine end to see how hard the lift pump was having to work, indicating fuel line constriction.

Don't forget the bug treatment biocide with every fuelling!

 

[prv]

I already have the Racor 500 unit on which this will fit.

Ah, now you tell us

Afraid I have no idea if there's an off-the-shelf adaptor available; I don't know what thread the filter housing uses. Quite likely NPT since they're American, which will complicate matters.

Someone like my grandad with a model engineering workshop in his back garden could turn one out in a morning from brass bar; sadly he's no longer with us but maybe you can find someone else to make what you need?

Pete

 

[Chris_Robb]

Ah, now you tell us

Afraid I have no idea if there's an off-the-shelf adaptor available; I don't know what thread the filter housing uses. Quite likely NPT since they're American, which will complicate matters.

Someone like my grandad with a model engineering workshop in his back garden could turn one out in a morning from brass bar; sadly he's no longer with us but maybe you can find someone else to make what you need?

Pete

I thought you were all referring to the Racor 500 series!!!

The fitting is as follows
[FONT=Arial, Helvetica, Verdana, sans-serif]Connection: 1/4" NPT thread, with 9/16" UNF thread fitting included. I am presuming that the 1/4 NPT (which I had never heard of) is the thread into the racor housing, and the 9/16" UNF is the size of the gauges thread.
So I need to look for a 9/16" UNF female to male 1/4" NPT.

Or I could just keep my fuel clean! which is easier said than done.[/FONT]

 

[prv]

I thought you were all referring to the Racor 500 series!!!

Nope - we had a pair of these (with separate changeover valves) on our old boat:

and now have one of these on the new one:

I'm actually not sure what the proper model designations for them are.

The fitting is as follows
Connection: 1/4" NPT thread, with 9/16" UNF thread fitting included. I am presuming that the 1/4 NPT (which I had never heard of) is the thread into the racor housing, and the 9/16" UNF is the size of the gauges thread.

I think your assumption is incorrect. I read it to mean that the filter housing inlet and outlet are 1/4" NPT, but because this is an American thread rarely used over here, the supplier is including a pair of 9/16" UNF adaptors to screw into them. I wouldn't expect them to list the dimensions and threads of internal parts like the assembly screw.

Pete

 

[Trundlebug]

... the only sure way is to cut an inspection hatch big enough to reach into. It's not that hard. We used a jigsaw, then cut a cover plate from sheet GRP, drilled securing holes round the edge of the cover, then fitted clinchnuts around the aperture to screw the cover plate on with. Cork gasket, no sealant.

It depends on what material your tanks are made of.
Mine are stainless. Trying to jigsaw a hole for a hatch isn't easy in stainless, although I grant you not a problem in grp, plastic or mild / galv steel.
That was the reason I only drilled a 10mm hole - apart from concerns over effective reasealing afterwards.

 

[pmagowan]

It depends on what material your tanks are made of.
Mine are stainless. Trying to jigsaw a hole for a hatch isn't easy in stainless, although I grant you not a problem in grp, plastic or mild / galv steel.
That was the reason I only drilled a 10mm hole - apart from concerns over effective reasealing afterwards.

I don't think resealing is a great problem, all you need to do is compress a gasket. If anyone decides to use an angle grinder or cutting torch then of course they should be very careful about the risk of explosion. Tanks could have water put in them to reduce this risk.

 

[prv]

Trying to jigsaw a hole for a hatch isn't easy in stainless

Seconded!

I went down to the boat armed with various tools to cut the hole. I started with a cheap drill-powered nibbler, but the end snapped off after a few mm of cut. In fairness, the thickness of the metal was larger than its stated capacity.

Then I tried a jigsaw with metal-cutting blades. Each blade went about a cm before the teeth were worn flat, and I only had five of them.

I thought of drilling a chain of holes, but I'd still need to saw between them, and I'd end up with a nasty jagged edge which would be even harder to smooth.

So the only remaining option was the 4-1/2" angle grinder. I'd already pumped out all the diesel I could reach through the sender hole, but of course there was still a little in there. I've heard all the talk about extinguishing cigarette ends in diesel, but I still didn't fancy directing a shower of sparks into it. So I poured in a bucket of soapy water to dilute and emulsify the diesel. I also hung wet rags around the engine bay and stoop-through to catch sparks there - and I got the big foam fire extinguisher out just in case

With 1mm disks the grinder cut the hole really quickly. The whole process was rather dramatic, but not at all difficult.

Finally I smoothed the edges carefully with a file, for the sake of my bare arm working through the hole.

Pete

 

[charles_reed]

Having the same problem, I had mine out and steam-cleaned. Worked a treat, but with many boats the fuel tank is impossible to remove.

 

[zambant]

Did mine via the filler cap ............

 

[prv]

Did mine via the filler cap ............

Good luck doing that down the two metres of hose from my cap to my tank

Pete

 

[Spirit of Glenans]

You could use water and then use something to absorb the water residue once pumped out(I think acetone works).

Alcohol, such as methylated spirit will absorb the water residue. Its also good for drying out wet electrical items.

 

[lw395]

Good luck doing that down the two metres of hose from my cap to my tank

Pete

3m hose and a steamer?

 

[Tim D]

A seven gallon tank shouldnt be too hard to clean out, I wouldnt bother mucking about with inspection hatch's, being stainless the inside surfaces should be clean from all this crud, It does sound like bug to me which survives in the layer between the water and the fuel, seven gallons isnt gonna cost much to use as burn up juice if you didnt fancy filtering it, I would simply pump it out via the tank draw pipe, disconnect the filter first then put it into a couple containers, let it settle then draw off the top the good fuel, in the mean time wash your tank with bilgex, pump it all out, a bit of new diesel to mop up any remaining bilgex/water, then refill it with your clean filtered red and new fuel not forgetting to add plenty of a good quality 2 part fuel treatment, and keep using the treatment each time you fill up, for the future a good precaution with such a small tank would be to fill a couple of 5 gallon see thru plastic cans with fuel, inspect it first before pouring it into your tank, at least that way you know if you have dirty fuel drawn from any fuelling stations tanks and can take the appropriate action.

 

[lw395]

Tim D is right except many tanks don't draw from the very bottom, so you need your pela with bigger bore hose to suck the crud and water out.
Last tank I did, by repeatedly pouring off the clean fuel, we got about 8 litres of clean fuel out of 10 litres of cruddy mess.
Just poured it into polythene milk bottles and let it settle for a few days.
We filtered the clean fuel through an old fuel filter (inline one off a motorbike!) and put it back in the tank.
No problems since, even without any additives.
We stick the pela in there every few months to see if it finds any water or crud, so far just about a few spoonfuls of water.

 

[Tim D]

I guess the water drain off tap at the bottom could take care of that problem regarding bottom drawing (providing one is fitted of course) reading back what I wrote and the last reply I realised im a bit of an idiot hehe hopefully you all wont agree, an idiot because one of my other suggestions was this which I totally forgot to post lol if you dont have the time or expertise or equipment etc to do the work yourself ...

http://www.ipu.co.uk/products/cleartank/

not necessarily this firm but its an example, there are firms out there who offer similar service's and some marina's will recommend a company to do such work.

 

[deep denial]

how do you actually cut an inpection hatch in a steel tank? It doesn't sound that easy