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

[Robert Wilson]

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.

'Fraid not. It's tucked away under the deck with about 2" clearance.

As an aside, I was informed today that Tampons are perfect for absorbing water. I think I shall give it a try, but not looking forward to going to the checkout at Boots..........

Got all the new filters, plus a length of new fuel line. Hopefully the wind will have eased tomorrow and I can get to the boat. Not a good forecast for later in the week

 

[Robert Wilson]

Well, that's the pumps cleaned through and new filters ready to fit (and re-locate the housings to a more convenient position).
I drained the tank this morning, but can still see a bit of brown gunge in the bottom.

I poured in some Startron and left it.

Do the wise ones think that if I put in a gallon (or two) of fresh diesel to mix with the Startron, leave it for a few days, then drain it out through the fuel line, then will that have got rid of the final bit of gunge?

As stated before, no inspection hatch, no drain tap and pick-up is a small distance from the bottom of the tank.

If not a valid action, what suggestions as to how to remove the final gung?

Thanks in Auntie Sepation

 

[Kelpie]

What's the acces to the bottom of the tank like? Anybchance of fitting a sump drain?

 

[lw395]

Well, that's the pumps cleaned through and new filters ready to fit (and re-locate the housings to a more convenient position).
I drained the tank this morning, but can still see a bit of brown gunge in the bottom.

I poured in some Startron and left it.

Do the wise ones think that if I put in a gallon (or two) of fresh diesel to mix with the Startron, leave it for a few days, then drain it out through the fuel line, then will that have got rid of the final bit of gunge?

As stated before, no inspection hatch, no drain tap and pick-up is a small distance from the bottom of the tank.

If not a valid action, what suggestions as to how to remove the final gung?

Thanks in Auntie Sepation

I use a pela oil extractor to hoover the bottom of the tank.
I change the tube on the pela for an 8mm bore with a 1/4 turn valve in it.
If you can heel the boat so the water and crud goes to one side it helps.
I keep removing diesel until it's coming out clean.
The diesel I remove is left to separate in polyethylene milk bottles, I pour off the clear stuff and filter it back into the tank.
What's left eventually settles to fairly pure crud and fairly pure diesel.

IMHO, you can never keep a tank totally clean for very long, so I don't bother.
I aim to keep the amount of crud down to a sensible level so worst case it should not be anything like the amount the filters can cope with.

 

[Robert Wilson]

I use a pela oil extractor to hoover the bottom of the tank.
I change the tube on the pela for an 8mm bore with a 1/4 turn valve in it.
If you can heel the boat so the water and crud goes to one side it helps.
I keep removing diesel until it's coming out clean.
The diesel I remove is left to separate in polyethylene milk bottles, I pour off the clear stuff and filter it back into the tank.
What's left eventually settles to fairly pure crud and fairly pure diesel.

IMHO, you can never keep a tank totally clean for very long, so I don't bother.
I aim to keep the amount of crud down to a sensible level so worst case it should not be anything like the amount the filters can cope with.

Encouraging. Thank you.
I reckon there's only a small amount of gunge (crud!) left now, so one more flush through should do the trick.

I have a diesel taste in my mouth and all my clothes stink of the stuff. Yuchk!

 

[Robert Wilson]

Lovely calm, sunny day today. All sorts of jobs done.
Then I decided the only way I was going to get rid of the gunge was to remove the tank. WHAT A JOB that was!
Tank "cradle" chopped/chiselled away, twisted and turned the tank past the exhaust through-hull and eventually got it to shore.
Loads of gunge still, so local garage is going to steam-clean it. Hopefully it'll be back in place by tomorrow afternoon.

Huge cost, huge hassle, filthy stinking boat and decks - all for the sake of not replacing a measly fuel filler "O"ring last year.

As I've said before, "If you learn by your mistakes, then I'm getting a fantastic education."

P.S. The good news:-
Once the tank was out, I found it has a drain plug (in a sod of a location, though)

The bad news is I broke the fuel shut-off tap. Rats :disgust:

 

[Kelpie]

Can you get an inspection hatch added whilst the tank is out?

 

[Robert Wilson]

Well I could but that would mean going to Inverness and the boat has to come out for scrubbing on Thursday, so not enough time. Need the engine to get from mooring to quay.
Also, the location under the deck would mean a whole in the side-deck which is not wide enough at that point.

It's a job for next winter. Inspection hatch and relocate fuel tank to an accessible position.

Despite Swarfega, soap and then a v hot bath with copious more soap - I still stink of diesel.

YUCHK.

 

[lpdsn]

Well I could but that would mean going to Inverness and the boat has to come out for scrubbing on Thursday, so not enough time. Need the engine to get from mooring to quay.
Also, the location under the deck would mean a whole in the side-deck which is not wide enough at that point.

It's a job for next winter. Inspection hatch and relocate fuel tank to an accessible position.

Despite Swarfega, soap and then a v hot bath with copious more soap - I still stink of diesel.

YUCHK.

In extremis, you could run the engine from a jerry can if you must come out on that date. Beware the return pipe though - first time I did it the engine cut out about five seconds after I'd come alongside as most of the contents of the can had gone down the return pipe (could've been worse).

I'd be wary of putting the inspection hatch on the side deck. You don't want water getting in

 

[Robert Wilson]

In extremis, you could run the engine from a jerry can if you must come out on that date. Beware the return pipe though - first time I did it the engine cut out about five seconds after I'd come alongside as most of the contents of the can had gone down the return pipe (could've been worse).

I'd be wary of putting the inspection hatch on the side deck. You don't want water getting in

Are, return pipe. Had thought of a temporary can, but omitted to consider the return pipe. THANK YOU:encouragement:

 

[charles_reed]

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.

I'd agree. When mine went that way I had it out and steam-cleaned through the filler. Alternative to using the filler is to fit an inspection hatch.
But, IMHO, anything else is merely palliative.
After that I did fit a coarse Rotax filter after the separator and before the fine one on the engine. In 8 years I've only drained the Rotax once (there was nothing in it), though the separator generally offers up a teaspoonful of water every 350hrs.
IMHO, once there's water in the tank you'll always have it there.

 

[Robert Wilson]

GOOD NEWS folks. After removal and steam-cleaning the tank was refitted today. All connected up and system bled - engine running sweetly.
PHEW!

Thanks for all you advice, warnings, encouragement and commiserations.

I sincerely hope my experience is a warning and also assistance to others.

Enjoying a VERY large Gin 'n' Tonic :encouragement:

 

[Kelpie]

Glad to hear it, I think that G&T is well earned.
Now go and ogle the lovely plastic tank that you're going to fit next year... they're amazing, you can actually see the crud in the bottom from outside.

 

[Robert Wilson]

Glad to hear it, I think that G&T is well earned.
Now go and ogle the lovely plastic tank that you're going to fit next year... they're amazing, you can actually see the crud in the bottom from outside.

But I don't want crud at all - never mind see it!!!

And pounds to pennies there wouldn't be one to fit

One good thing to come out of this whole sorry saga is that having flogged-on throughout I know a lot more about the mechanics and fuel set-up and have gained experience in tearing the boat to bits. Got the cuts and bruises to show for it too!:encouragement:

 

[charles_reed]

Learning is never painless.

Though I've had fuel blockages, never a complete filter block - only once anything (iron oxides) in the fine filter. What happens is a piece of tar-like substance, blocks the pick up pipe, usually after a turbulent passage.
My answer to that has been to raise the level of the pipe so there is more free space under the end. It does mean you have marginally less fuel reserve, but the other benefits are considerable.
My tank is tall and thin, doubt a flatter tank would allow such a work-round.
I fear that using bio-diesels will probably exaggerate this tendency because the "nuggets" are all long-chain polymers. So much for the EC's obsession with using old frying oil.
PS one of the advantages of red diesel - in the rest of Europe one has to use road diesel (and pay the tax).