Hey ho! Water in my diesel tank & filter. How to flush through?

[Robert Wilson]

Grrr, engine stopped today, water in diesel. How to clean tank?
After I have drained all the fuel from tank, pipes and filters, how do I "flush out" the tank before refilling?
Is there a "special" product, can I use a wee bit of detergent rinsed with petrol then diesel?

I cannot get at the underside of the tank, there is no drain tap and I guess there will be gunge in the tank.
So it's a "pipe-off and drain into container" job. But I want to make 100% sure my tank and pipes are totally clean before replacing the filters and refilling.

Please don't come over all "superior", this is the first time this has happened to me. And I know how/why it happened which will be remedied.

 

[superheat6k]

Firstly water is not that big a problem, as long as you are alongside somewhere, and the fuel remains quite useable.

I have a fuel polishing system, which is a simple Baldwin separator filter, with a 12V holley fuel pump, the pumps draw the fuel through the filter and back to the tank. You can use a wandering suction pipe to hoover the bottom of the tank.

If you get much cruddy muck out then a thorough shock treatment with Fuelset, Marine 16 or Grotamar will kill any bug.

Do you know how the water got there ? Check the filler seal is OK, and grease the filler threads thoroughly.

There is a picture of my fuel polisher on my blogsite - details below.

 

[sutton sailor]

I would advise that you also install permanantly another combined water trap and fuel filter between the tank and lift pump. This should catch any other water or dirt from the tank.

 

[Cloven]

Had the same problem some time ago due to a split washer in the filler cap. Fortunately my tank has a big inspection plate on the top. Pumped out all the old fuel and then thoroughly cleaned out the inside by hand with cloths, paper towel etc. Drained water from the water separator, changed filters and refilled tank. Been fine for the last 8 years.

 

[Robert Wilson]

Had the same problem some time ago due to a split washer in the filler cap. Fortunately my tank has a big inspection plate on the top. Pumped out all the old fuel and then thoroughly cleaned out the inside by hand with cloths, paper towel etc. Drained water from the water separator, changed filters and refilled tank. Been fine for the last 8 years.

Yep, washer had gone and I'd made a "washer/seal" of Sikaflex. Temporary repair didn't last long enough - we've had a LOT of rain with storm winds for weeks.
So that's how the water got in.
As for the inspection hatch - lucky you. Tank is totally sealed and under the deck. So can't get in apart from the filler 50mm tube.

Secondary (primary, actually) filters will be fitted, in fact I have them ready to fit - but job got delayed due to storms.

Once I drain the tank I'll dispose of the 2 gallons as waste. But it's ensuring the tank is totally clean which is my concern.

I'll get some Fuelset, Marine 16 or Grotamar to kill any bug that might be in there.

Thanks guys.

RW

 

[theoldsalt]

I'm sorry to give bad news but with no inspection hatch the only way to be sure there is not a layer of crud in the bottom of the tank and to thoroughly clean it is to remove it - even if you did have a drain in the bottom. Bin there, done that.

 

[Kelpie]

Would it not be potentially quite serious if the engine stopped due to water in the fuel? i.e. doesn't that mean water must have got to the injectors/cylinders?

 

[Robert Wilson]

I'm sorry to give bad news but with no inspection hatch the only way to be sure there is not a layer of crud in the bottom of the tank and to thoroughly clean it is to remove it - even if you did have a drain in the bottom. Bin there, done that.

Would it not be potentially quite serious if the engine stopped due to water in the fuel? i.e. doesn't that mean water must have got to the injectors/cylinders?

Not good news to start the day...................

Major job to remove tank; the guys who built it in (1970/80s) BUILT IT IN :nightmare:
I do have a borescope inspection gizmo which should show me what's in there. Getting any crud out is another matter.

As for water in the injectors/cylinders, I am very worried that you may be right.
I hope it will be possible to flush injectors through and there may be only minor accumulation in the cylinders (if any)

FINGERS Xd

 

[GeorgeLlewellin]

Fuel injector pump and injectors.

Grrr, engine stopped today, water in diesel. How to clean tank?

First things first, others here have already given you good advice about cleaning your fuel tank. I would concentrate on the injector pump and injectors. These are the items that could cost a whole lot more money if not dealt with quickly, the tank you can deal with later.

First drain the fuel injector pump, and I mean drain not bleed. Bleeding it will get the air out but leave any water in the pump, water can do a lot of damage especially if it is salt water. Disconnect all injector pipes, the supply pipe, open the bleed screw and the excess outlet at the top of the pump then open any plug or remove covers so as to drain the pump from the bottom. Flush out and replace.

Now make sure that all filters etc. downstream from the lift pump are clean, connect up the injector pump and connect a temporary supply container of clean fuel to the lift pump, bleed the system. Try turning over and note if fuel is being ejected from the injector pump connections points. Reconnect the injector pipes.

A few important points before you start the engine.
1. Do not forget the excess fuel return pipe, if you let this drain into a large glass container you will be able to see if any water is passed through.
2. With the excess being returned to a separate container, the temporary supply container will get used up very quickly, if the initial few minutes of return fuel is clean you could then move the returns pipe to the temporary supply container.

Start the engine and run, best if the boat is in the water and you can run while tied up and under load, this will force much more fuel through the system and make sure it all works and is thoroughly flushed out.

There may well be no damage to the injector pump and injectors, however this procedure will minimise any further damage and let you know if it works or not.

Good luck, George.

 

[Appledore]

I only have a small tank on my boat, and have often removed it to get any water/crud out of it. Last year I just used a Pela oil extractor pump and 'hoovered' around the bottom of the tank to remove any water and muck. Might be possible if you can access through the top of the tank somehow??

 

[Robert Wilson]

First things first, others here have already given you good advice about cleaning your fuel tank. I would concentrate on the injector pump and injectors. These are the items that could cost a whole lot more money if not dealt with quickly, the tank you can deal with later.

First drain the fuel injector pump, and I mean drain not bleed. Bleeding it will get the air out but leave any water in the pump, water can do a lot of damage especially if it is salt water. Disconnect all injector pipes, the supply pipe, open the bleed screw and the excess outlet at the top of the pump then open any plug or remove covers so as to drain the pump from the bottom. Flush out and replace.

Now make sure that all filters etc. downstream from the lift pump are clean, connect up the injector pump and connect a temporary supply container of clean fuel to the lift pump, bleed the system. Try turning over and note if fuel is being ejected from the injector pump connections points. Reconnect the injector pipes.

A few important points before you start the engine.
1. Do not forget the excess fuel return pipe, if you let this drain into a large glass container you will be able to see if any water is passed through.
2. With the excess being returned to a separate container, the temporary supply container will get used up very quickly, if the initial few minutes of return fuel is clean you could then move the returns pipe to the temporary supply container.

Start the engine and run, best if the boat is in the water and you can run while tied up and under load, this will force much more fuel through the system and make sure it all works and is thoroughly flushed out.

There may well be no damage to the injector pump and injectors, however this procedure will minimise any further damage and let you know if it works or not.

Good luck, George.

I stitch in time missed is going to cost a lot of aggro! Hopefully, not a lot of ££££S

Thank you George for that comprehensive advice. The only two bits of cheering news therein is the boat is in the water and it wasn't sea-water that got into the tank.

The engine slowed to a stop. I tried a brief turnover on the ignition, but stopped trying within a few seconds.

I will have plenty on this week and next prepping for my trip, so I think the engineer will be called-in. He knows a lot more about the engine than I do!!

Thanks again,
RW

PS. Where abouts in Pembokeshire are you? I'm going to see Rob Mason near Hook on May 9th - may bump into you if you're around.

 

[Cloven]

Excellent advice from GeorgeLlewellin. When I had the sme problem, Ref #4 above, this is exactly what I had done to my engine, fortunately by a friend who realised the urgency of getting it running & had it done within an hour of it stopping. No damage and it has run well for the last 8 years.

This was the spur for me to find out all I could about maintaining my engine. Did the RYA diesel maintenance course, OK but not specific enough so I employed the marina engineer for a couple of hours to take me through all the likely basic problems and how to fix them and also basic annual servicing. Important thing was to actually do the things myself, under supervision, rather than just watch someone else do them. Best money I ever spent on the boat.

 

[Robert Wilson]

Excellent advice from GeorgeLlewellin. When I had the sme problem, Ref #4 above, this is exactly what I had done to my engine, fortunately by a friend who realised the urgency of getting it running & had it done within an hour of it stopping. No damage and it has run well for the last 8 years.

This was the spur for me to find out all I could about maintaining my engine. Did the RYA diesel maintenance course, OK but not specific enough so I employed the marina engineer for a couple of hours to take me through all the likely basic problems and how to fix them and also basic annual servicing. Important thing was to actually do the things myself, under supervision, rather than just watch someone else do them. Best money I ever spent on the boat.

I've just spoken with my engineer who echoes all the above. I'm hoping to get a lift to the boat this afternoon or tomorrow and get it fixed. I hadn't realised that time is so critical.

What an absolute barsteward to have this happen now!

Hey Ho.

Thanks again

 

[Robert Wilson]

First stage done.
Engineer and I today drained the tank, filter and pump(s). What a sludgy mess!
Engine now working again on stand-by tank.(2 gallon can actually).
Next stage is to get new filter in Inverness tomorrow, refit it, join all the pipes up again and bleed through from tank - once it has been fully drained and filled with fresh diesel and additive.

Spilt diesel all over the deck and my clothes in freezing sleet and at LEAST force 12 winds .
I reek of diesel - and so does the boat.
Bleeeaaaahhhh.

 

[MM5AHO]

I have a simple method of cleaning gunk and water from my diesel tank. I have no inspection hatch and removal of the tank would be a major job.

I found a 2 litre milk bottle - plastic, used, cleaned and dried.
Bored two holes in the lid and sized for some small bore clear plastic hose. (about 6-8mm outside diameter, perhaps 5mm ID),
Cut 2 lengths of the hose. One piece about 300mm long, the other about 1m long.
Insert hoses into lid, short piece about 50mm in, long piece about 100mm in, replace lid.

Now suck on the short piece, create some vacuum in the bottle.
Insert other end through filler cap till it hits bottom. Watch the gunk get vacuumed up as you provide the suction by sucking.
Don't go past about half full in the bottle, you then risk a mouthful of diesel. Just empty into something and continue.
Move the long hose about a lot, along the length of the tank, and keep vacuuming until the diesel runs clear.

Its a very low cost way to clean up the tank.
Pumps etc are better (no risk of a mouthful, though I've yet to taste any).

 

[Robert Wilson]

I have a simple method of cleaning gunk and water from my diesel tank. I have no inspection hatch and removal of the tank would be a major job.

I found a 2 litre milk bottle - plastic, used, cleaned and dried.
Bored two holes in the lid and sized for some small bore clear plastic hose. (about 6-8mm outside diameter, perhaps 5mm ID),
Cut 2 lengths of the hose. One piece about 300mm long, the other about 1m long.
Insert hoses into lid, short piece about 50mm in, long piece about 100mm in, replace lid.

Now suck on the short piece, create some vacuum in the bottle.
Insert other end through filler cap till it hits bottom. Watch the gunk get vacuumed up as you provide the suction by sucking.
Don't go past about half full in the bottle, you then risk a mouthful of diesel. Just empty into something and continue.
Move the long hose about a lot, along the length of the tank, and keep vacuuming until the diesel runs clear.

Its a very low cost way to clean up the tank.
Pumps etc are better (no risk of a mouthful, though I've yet to taste any).

Low tech, low cost, low hassle. Brilliant.
You have just sorted a problem that woke me at 04:00 this very wild, very wet morning.
Many thanks.

 

[Kelpie]

If you have a small pump for doing oil changes, that is a little less harmful to your health

 

[aquaplane]

In the Lab we use a solvent that is micible in the organic phase (diesel) and the water to clean out gungy mixtures.

Meths or other alcohols are suitable.

It could be a way to dry out your system but I would be sure to make sure you get rid of most of it before filling with diesel.
Certainly make sure your pump is flooded with diesel before running it, the alcohol won't have the same lubricating properties as diesel.

 

[lpdsn]

In the Lab we use a solvent that is micible in the organic phase (diesel) and the water to clean out gungy mixtures.

Meths or other alcohols are suitable.

It could be a way to dry out your system but I would be sure to make sure you get rid of most of it before filling with diesel.
Certainly make sure your pump is flooded with diesel before running it, the alcohol won't have the same lubricating properties as diesel.

Based on a vague recollection of A level Chemistry I experimented a bit using Meths as a water absorber. Unfortunately, the Ethanol and water combine to form a white sludge (well pink actually seeing as it was meths) so I had to abandon the idea.

 

[lpdsn]

As for the inspection hatch - lucky you. Tank is totally sealed and under the deck. So can't get in apart from the filler 50mm tube.

Inspection hatches really are worth it if there's any way you can fit one.

Is there no way you can even reach the top surface of the tank to cut a hole? Obviously take all the necessary precautions to ensure cutting into the tank doesn't make it go bang.

Mine was built with one, but when I looked into it, it turned out they'd used a cover for an emergency tiller from Solimar as the inspection hatch. Works though.