Rust in diesel tank

[shell]

Does anybody have a bright idea on how to clean rusty deposits out of the bottom of my diesel tank? I can ultimately remove the tank but it means removing engine too! There seems to be quite a bit slushing around, it stopped my engine dead this summer by blocking the fuel tap

 

[RobBrown]

What about a Pela Pump or similar ? I have only used one for engine & gear box oil extraction, but I seem to recall several peeps here suggesting using to get gunge out of fuel tanks. I guess the problem might be the risk of blockage if it is mainly large particles of rust, but might be worth a try & if you haven't got such a device, they are worthwhile getting just for the "standard" use.

 

[ms1]

I would suggest chunky hand suction pump and hoover round the bottom of the tank with a connected length of stiff plastic pipe (a la Homebase) discharge into a couple of empty 5L mineral water containers (you can even filter these out and put the clean fuel back) if its flakey rust you have you'll need a big bore to suck it up.
best done with 2 pairs of hands

 

[PeterGibbs]

Most of us have some accumulations in our tanks - if not quite a tough as you describe! May I suggest you follow the advice given to suck out the main junk even filter the removed fuel and use it to wash the base of the tank again.

The very fine stuff will be almost impolssible to totally remove - but then the filters should take care of that. Assume you have at least 2 in line? Worth inserting a second if not - one with glass inspection bowl.

Suggest you then check the first filter soon after cleaning the tank, and be prepared to replace if it's beginning to fill with debris.

This way you'll avoid removing the tank - only really necessary in the event of gross loss of integrity. By the way, where did all this junk come from? Hope you've put a stop to that...?

I used to pay more attention to the oil filter on my boat, until a wise owl said, change tack - you'll do much more good keeping the fuel flow clean by changing fuel filters more often. How right he was!

One PS - if you've been sucking a lot of rubbish through your engine of late, it's just possible the fuel lift pump has taken a knock. Be prepared!

PWG

 

[shell]

Thanks for the suggestions, I can't see a way to hoover the bottom of the tank. I presume you do this through the filler neck? Mine has a few sharp bends in it, the last one is at 90 degrees to the tank. The opening for the fuel tap is also no larger then 1/2".
The filters are changed regularly, this stuff blocked the first restriction it came across, the fuel valve.
I suppose it might come down to removing the engine, good excuse for a nice cleanup, paint job and replace mountings.
/forums/images/graemlins/ooo.gif

 

[rutten]

My diesel tank is integrated in the keel of my steel boat. I cleaned it using a Wolfcraft impeller pump (cheap, garden center) that can be mounted on a power tool. Used a hose connected to copper tube to get to the bottom of the tank. Takes large metal bits. When filling cans take care to tighten the hose to the can. Of course, I did not and felt like Donald Duck.
Let debris sink in cans in a few days, pour through coffee filter, give the cleaned diesel back into the tank and repeat the process. Dismantle the pump and clean after each use to prevent the impeller from sticking.
I have now a day tank, plastic, 25 liters, double fine filters after it in parallel (if one goes down I can switch in the other) and a Vetus 250 filter in front of it. Day tank is filled before departure, when all remaining or reborn debris is at rest at the bottom.
I must pay tribute to Pat Manley, who advised me in this.

 

[Haven't-a-Clue]

To avoid getting cr*p in your pump, you could try doing what we do in the op. theatre with our suction units i.e. attach your pump to a large jar (plastic or glass) with a screw top or tight fitting lid. Drill 2 holes in the lid and fit 2 lengths of suitable pipe through the holes, one going to just above the bottom of the jar and one short stopping just inside the jar. Attach the pump to the short pipe and the hose to the tank to the long one. This way, you'll be able to see any rubbish in the jar. PM me if (as I suspect!) this description isn't making sense!

 

[PeterGibbs]

Can you get to the spiggot where the fuel filler pipe enters the tank? Remove the pipe and pump out contents using one of these pumps on an electric drill - easy. Or use a hand pump.

Failing this, there's nothing to prevent you making a 3-4cm hole in the top of the tank - it's what fitters do to draw fuel for heaters and the like - and getting in there with the hose and pump. Close the top with a proprietary closure - good for future use!

Given the engine realignment and everything else I would shudder at shaking the whole system up - lots of scope for doing damage along the way..

PWG

 

[boatmike]

I have a pet hate for steel tanks without a reasonable inspection hatch. If you can get to the top of it I would fill it with water to prevent fire and grind out an inspection hatch big enough to get an arm through. Easily closed with a mild steel plate and a series of bolts with a flat rubber gasket. You may well find there are internal baffles in the tank and it is impossible to get all the crap out otherwise.

 

[Anonymous]

Hi, and welcome to the forum. I've been thinking overnight on your problem and honestly there is no good quick fix that I can think of. You should get the tank cleaned out and inspect it otherwise you could be plagued with trouble. Engine failure at sea is not good.

If you really cannot do that then you could possibly consider a Separ filter/separator between the tank and the first of your existing filters. Then inspect the Separ regularly. Some fuel systems feed back unwanted fuel from the injectors back to the tank continually (when the engine is running /forums/images/graemlins/wink.gif) so your Separ would clean up the tank and fuel - cleaning fuel is called 'polishing'. Maybe your tank deterioration is not too bad and you can live with it but you need to check that the tank is solid enough not to fail in service. Pressure testing is the usual way especially if you can't get right round it or inspect the inside.

If it was my boat, and I planned to keep it, I would bring forward the engine full overhaul to the top of the list and do both the engine and tank over the winter.

 

[shell]

I don't think I'll be able to get a hose in, the spigot is very tight to the cockpit flooor. Cutting a hole in the tank is a good option but as somebody mentioned there might be baffles....
Fitting a larger fuel tap and a trap straight after it might work I suppose.
Is engine realignment difficult? /forums/images/graemlins/tongue.gif Is it just a case of fitting new mounts and remounting it or is there a "special procedure"
Engine is MD7B.

 

[captainslarty]

ususally baffles will be indicted by spot welds on the tank top / side.. cutting a hole in the top is no big deal.. even full of diesel !.. I had to do it in France when the main tank baffe detached itself from the top !!!.. (Stainless tank).. have since added a large inspection hatch, and, a drain tap to the sump bottom, but luckily, our tank is easy to get at.

Best option for me would be to cut a hole in the top about 6" across. make a plate slightly larger to cover it later. Then get the crappo out and use a torch to inpect. try to keep the tank full afterwards.
Joe

 

[boatmike]

It were me wot sed it.... Baffles are usually welded to the sides or bottom but if they are on top you will I agree certainly see weld witness on the outside. I would still cut a gert big ole in the top. DON'T do it without draining the diesel first and filling with water though. You will PROBABLY be OK with fuel still in the tank but you will contaminate it even more with swarf even if you don't blow your ass off...
You have to clean the tank out thoroughly afterwards anyway so it's not a problem. Just avoid getting water in your fuel system. If you havent got a tap this is the ideal time to fit one!