Cloudy diesel and longevity of diesel

[n-baj]

Hello all, I would like some opinions and experiences of the longevity of diesel. It’s a little long winded but please bare with me.

 

Last summer I was having issues with the engine getting fuel starved. Had the diesel polished, replaced the lift pump, added loads of marine 16, etc. In September I finally snapped after the 12th breakdown and installed a fuel inspection hatch where I found a plastic end from a mop handle. Great I thought, that would block the intake pipe. I also took the opportunity to clean the bottom of the tank and dispose of the crappy diesel before filling up for the winter.

 

I filled up Jerry cans and topped off the tank late September. I added some marine 16 preventative additive (the tea coloured liquid, not the shock treatment).

 

In mid October I topped off the tank using the Jerry cans.

 

In Mid December I took a sample of diesel from the water trap of the primary filter - picture 1 and 2 shows its nice and clean diesel. At this point the tank is about 3/4 full.

 

Today with the tank a little less than half full I’m horrified to see loads of water in the water trap and emulsified cloudy diesel coming out (picture 3 and 4).

 

I know about keeping tanks full or nearly full but unfortunately where I winter there is no fuel boats or canal side red diesel to keep the tank topped up (although there is a petrol station selling derv).

 

I’m just after opinions and experience from others in this subject - does your diesel go cloudy like this over the winter when the tank isn’t filled? 

 

Is diesel now really that hydroscopic that it cannot last 6 months over winter in a tank? 

 

I’m I overthinking the state of the diesel? Is it a case of just putting in some fresh diesel, regularly draining the water trap and it will get better again over the summer?

 

I can only think it’s tank condensation, if it was a hatch and/or filler cap leak then there would be signs of water in December.

 

Many thanks!

[Tony Brooks]

The bio content (7%?) is certainly hygroscopic, and it seems to make the diesel go cloudy pink. I would not be so ready to write the filler cap off if it is a male cap with an O ring. If it is then when did you last replace the O ring, and when did you last dress it with silicon grease? I think that I would change the filter, cut it open, and look for signs of bug. Are you sure that your Jerry cans are bug free, but most likely water.

[n-baj]

Thanks for your reply Tony.

 

the filler cap is one of them lockable ones where the lid overlaps onto the tank as opposed to one of them male caps that does leak water with a perished o ring. The inspection hatch has a gasket and the hole is much smaller than the lid (see pic for reference)

 

regards to diesel bug I put so much shock treatment in last summer that I would have though the diesel is sterile. I put that diesel into Jerry cans to install the hatch so I would have thought there’s no bug but I cannot prove it. 
 

The fuel tank vent is situated inside my stern cratch cover and it’s never taken down over winter. On some mornings there’s so much condensation that the water is dripping off the ceiling on the cratch cover. Maybe when the tank breathes it takes in some of this moisture?

[Tony Brooks]

Thanks, but how is the filler cap keyhole sealed? It looks as if there are recesses that will hold water in the centre of the cap.

 

Tanks do suffer from internal condensation, but from what you said, it seems yours may be more than that. Traditionally, the advice was to keep tanks full over winter to minimise the airspace for condensation to form. This winter has seemed exceptionally wet and damp to me.

[Tracy D'arth]

Where is the tank vent?

[n-baj]

20 minutes ago, Tracy D'arth said:

Where is the tank vent?

It is behind a wooden box (pic 1). Pic 2 is with the box removed

[Tracy D'arth]

With that design of vent in the rail you get massive condensation in the steel tube! Many of them rust away badly.

[Ex Brummie]

could you be overdosing the fuel treatment?

The only fuel problem I've ever had was after using a treatment. When calculating the dosage rate for small volumes it is too easy to be heavy handed.

[Bee]

You have been unlucky for some reason. It might have nothing to do with your problem but the canal in pic. 5 has a bit of diesel floating on it, you might have a pinhole in the tank (?) My guess is that water has got into the tank, either from the inspection plate (Very sensible to fit that) or the filler cap or some sort of problem with the tube that the rudder shaft goes through. I fear that you might have to take the inspection plate off and have a good look and clean the thing out again - this might give you a clue where the water is coming from. Water in fuel is a sod to sort out. Personally I have not got much faith in fuel additives and my experience with cloudy fuel is that it will not burn but it might just damage the engine as it is incompressible. Good luck!

[Tony Brooks]

7 minutes ago, Ex Brummie said:

could you be overdosing the fuel treatment?

The only fuel problem I've ever had was after using a treatment. When calculating the dosage rate for small volumes it is too easy to be heavy handed.

 

Certainly, the emulsifying type additive will   create cloudy fuel when water is emulsified in the fuel.

[n-baj]

1 hour ago, Tracy D'arth said:

With that design of vent in the rail you get massive condensation in the steel tube! Many of them rust away badly.

Yes that makes sense Tracy thanks

 

1 hour ago, Ex Brummie said:

could you be overdosing the fuel treatment?

The only fuel problem I've ever had was after using a treatment. When calculating the dosage rate for small volumes it is too easy to be heavy handed.

 

Thanks for your reply. I last put in marine 16 in September and had clear diesel in December, also I believe marine 16 is a de-emulsifier which causes the emulsified  water to drop into free water.

1 hour ago, Bee said:

You have been unlucky for some reason. It might have nothing to do with your problem but the canal in pic. 5 has a bit of diesel floating on it, you might have a pinhole in the tank (?) My guess is that water has got into the tank, either from the inspection plate (Very sensible to fit that) or the filler cap or some sort of problem with the tube that the rudder shaft goes through. I fear that you might have to take the inspection plate off and have a good look and clean the thing out again - this might give you a clue where the water is coming from. Water in fuel is a sod to sort out. Personally I have not got much faith in fuel additives and my experience with cloudy fuel is that it will not burn but it might just damage the engine as it is incompressible. Good luck!

that is a frightening thought! I’ve not noticed a film of oil around my boat but I will keep an eye out for it again. The water trap is doing its job so I’m not too concerned with water making it way into the engine. The engine doesn’t smoke at all (apart from a little blue smoke when warming up). 
 

I might be wrong but the fact it’s all pretty much emulsified water and the only free water is in the water trap would suggest to me it is the hydroscopic element of the diesel rather than leaking fuel caps, inspection hatch or (god forbid) a hole in the rudder tube as these sorts of water ingress will surely just collect as free water on the bottom of the tank?

 

also I’ve just heated up a sample and after producing a little steam the diesel turned clear. Is there an element of waxing occurring too while the canal water is still cold and the diesel looks worse than it actually is?

Edited April 2 by n-baj

[Alan de Enfield]

8 minutes ago, n-baj said:

Is there an element of waxing occurring too while the canal water is still cold and the diesel looks worse than it actually is?

 

There could be.

Summer grade diesel is generally changed to Winter grade at the end of September, so you probably have 3/4 full tank of Summer Grade diesel.

But I wouldn't have thought it was cold enough at the moment to cause waxing.

Summer grade starts to 'thicken' at just below 0 degrees C and forms wax crystals at -4 degrees C

[n-baj]

Hello all a little update. 
 

I’ve moved since that post and in my new spots there’s no oil slick so I can thankfully rule out stock tube leak 😃

 

I’ve opened the inspection hatch and took a sample of diesel on the top and it’s just as milky so it’s not separating out. I’ve also pumped from the corner and got a minimal amount of water (literally 30-50ml).

 

the pick up pipe for some reason only known to STS boats picks up the fuel from the bottom so any little water will end up in the trap. I plan going forward to regularly drain the water trap.

 

I’ve changed the filters, and cut the old ones open on the advice of Tony. pic 1 is the primary which looks like it does have strands of bug however these filters have been in use before I cut the hatch and cleaned the bottom of the tank. Pic 2 is the secondary which is clean. 
 

pic 3 is interesting, this shows white flakes from the water trap. (the brown bits are gritty so not bug) so I’ve took a sample with the white flakes and after some heating they disappear and the diesel goes clear. I can only conclude that the white flakes is waxing left over from the winter and also the milky appearance may be waxing that simply hasn’t dissolved back into the diesel?

 

the diesel heater still works and the engine runs fine (apart from a fuel starvation issue a few days ago but I had a rubbish £3 Alibaba special lift pump fitted, now replaced with a facet posi-flo). However as I do tidal at least twice a year I am a little paranoid about fuel quality and engine maintenance in general.

 

comments are appreciated 

 

many thanks 

[Tony1]

On 02/04/2024 at 18:32, n-baj said:

 

also I’ve just heated up a sample and after producing a little steam the diesel turned clear

 

 

I think you've just invented a new cocktail there Mr Baj- try it as a chaser, with a slice of lemon and some tonic. 

I'm afraid I cant moor next to you any more in case my boat catches the bug from yours. 

 

[n-baj]

3 minutes ago, Tony1 said:

 

I think you've just invented a new cocktail there Mr Baj- try it as a chaser, with a slice of lemon and some tonic. 

I'm afraid I cant moor next to you any more in case my boat catches the bug from yours. 

 

I might do, the high energy content of diesel will render expensive food obsolete so I can save some cash 😃

 

as long as you put a mask on your boat it should be fine 

[Tony Brooks]

I think it is the bio content that is emulsifying, but have no idea how to stop it, apart from stopping water getting into the fuel, but then it might have come in with the last fill of fuel. At one time some canal side fuel suppliers were adding emulsifying additives to their bulk tank, no idea if they still do.

 

Then there is still the possibility of waxing, but like Alan I don't think that it has been cold enough and the filters show no signs of wax platelets.

[n-baj]

2 minutes ago, Tony Brooks said:

I think it is the bio content that is emulsifying, but have no idea how to stop it, apart from stopping water getting into the fuel, but then it might have come in with the last fill of fuel. At one time some canal side fuel suppliers were adding emulsifying additives to their bulk tank, no idea if they still do.

 

Then there is still the possibility of waxing, but like Alan I don't think that it has been cold enough and the filters show no signs of wax platelets.

Thanks Tony I’m at the point of suck it up, stop worrying and enjoy boating, I tend to overthink things sometimes. HVO will hopefully be a commonplace soon which I believe is a far superior fuel to the current stuff we get.

[Tony1]

 

 

Just a thought, but that nasty fuel will also be going into your Eberspacher, which might not be great? 

I'd be tempted to get the lot pumped out and disposed of, rinse out the tank a bit and refill it with new clean fuel plus a shock treatment of marine 16. 

Over the summer you can keep it frequently topped up and free of bug, and cruise knowing you're not doing the engine any harm etc.

I had a bout of it in winter 21/22, but after that I keep it topped up every 2 weeks when the fuel boat visited (sometimes only 20-30 litres), and touch wood its been great since.

Its odd that it seemed to get worse after you installed the inspection hatch... 

 

Edited April 6 by Tony1

[Alan de Enfield]

55 minutes ago, n-baj said:

I’ve opened the inspection hatch and took a sample of diesel on the top and it’s just as milky so it’s not separating out. I’ve also pumped from the corner and got a minimal amount of water (literally 30-50ml).

 

the pick up pipe for some reason only known to STS boats picks up the fuel from the bottom so any little water will end up in the trap. I plan going forward to regularly drain the water trap.

 

I’ve changed the filters, and cut the old ones open on the advice of Tony. pic 1 is the primary which looks like it does have strands of bug however these filters have been in use before I cut the hatch and cleaned the bottom of the tank. Pic 2 is the secondary which is clean. 
 

pic 3 is interesting, this shows white flakes from the water trap. (the brown bits are gritty so not bug) so I’ve took a sample with the white flakes and after some heating they disappear and the diesel goes clear. I can only conclude that the white flakes is waxing left over from the winter and also the milky appearance may be waxing that simply hasn’t dissolved back into the diesel?

 

 

I've seen far far worse filters and the engine ran fine.

 

I'm wondering if your fuel starvation problem is actually an 'air leak' in a joint or filter, or 'pin prick', somewhere in the system so it's sucking air & making it run "lean".

 

The 'filthy' diesel is not helping and although I have tried, an engine won't run on water (I had 200 litres of water in my tank)

Maybe consider 'scrapping' the fuel or get it cleaned (it costs about the same to get fuel cleaned as it does to buy 'fresh fuel')

 

You need to start with a clean fuel system (from tank to injectors), before you can really start to fault find.

[n-baj]

29 minutes ago, Tony1 said:

 

 

Just a thought, but that nasty fuel will also be going into your Eberspacher, which might not be great? 

I'd be tempted to get the lot pumped out and disposed of, rinse out the tank a bit and refill it with new clean fuel plus a shock treatment of marine 16. 

Over the summer you can keep it frequently topped up and free of bug, and cruise knowing you're not doing the engine any harm etc.

I had a bout of it in winter 21/22, but after that I keep it topped up every 2 weeks when the fuel boat visited (sometimes only 20-30 litres), and touch wood its been great since.

Its odd that it seemed to get worse after you installed the inspection hatch... 

 

The tank pre hatch was in a diabolical state, all sorts of crud at the bottom, which was probably the downfall of the last eber when we was on the bridgewater, all it is now post hatch is this milky diesel. 

 

17 minutes ago, Alan de Enfield said:

 

 

I've seen far far worse filters and the engine ran fine.

 

I'm wondering if your fuel starvation problem is actually an 'air leak' in a joint or filter, or 'pin prick', somewhere in the system so it's sucking air & making it run "lean".

 

The 'filthy' diesel is not helping and although I have tried, an engine won't run on water (I had 200 litres of water in my tank)

Maybe consider 'scrapping' the fuel or get it cleaned (it costs about the same to get fuel cleaned as it does to buy 'fresh fuel')

 

You need to start with a clean fuel system (from tank to injectors), before you can really start to fault find.

The engine is a barrus shire so the system goes tank->lift pump->primary->secondary->engine->tank so most of the system is under positive pressure and is self bleeding. It is also all under the pick up pipe in the tank so there’s an element of syphoning too.
 

The past couple of starvation issues is the rubbish electric lift pump which has been documented on this forum in the past from other barrus shire owners. Hopefully the faucet pump with an inline 74 micron filter between the pump and tank will sort out this issue. Most of the breakdowns I had last summer was caused by a plastic thing inside the tank belonging to an end of a mop which was only discovered when I installed an inspection hatch in September (pictured)

 

a worrying thought as I was the Ribble link and tidal Ouse last year with that inside the tank

Edited April 6 by n-baj

[Naughty Cal]

We always found that using fuel rather than storing it was the best way to keep it clean!