Diesel Bug?

Poey50 said:
I had a bad dose of bug that came free with the boat on purchase in 2016 since she hadn't been used for about 18 months. Our tank is also very tricky to move so I haven't!

I built a fuel polisher and use this at the start and end of every season. I also dose every batch with Marine 16 and am scrupulous about sealing the fuel cap threads with soft grease to avoid water getting in. Tank condensation has been demonstrated to be a myth so I don't bother filling before layup. I've never had any problem since.

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Your success lies in using the M16 ..... not my first choice additive - but it works.

As to condensation being a myth ........... sorry but you are wrong. The amount of moisture needed is actually minute and does not have to be visible ... the moisture content of diesel is sufficient .. add a bit of condensation .....

Finally - every time this subject comes up I mention that the common perception that bug is just a single bug is wrong. The 'bug' matter comes in the ranges of : Y -M - B .... Yeasts - Molds - Bacteria ... it then subdivides even further into those that thrive in the moisture interface and those that survive via the Sulphur - SRB = Sulphur Reducing Bacteria.

Steam and then chemical cleaning of tank - or if not possible - emptying tank as fully as possible, change filters, blow through lines and then introducing fuel with high dosage of Enzyme Biocide
High dosage Enzyme based Biocide for first fuel initially
Regular maintenance dosing by Biocide

That should keep most happy and running well.
 
Poey50 said:
Tank cleaning goes with theory that you can and should eliminate the bug. I think that's unrealistic and the alternative is to accept that some bug is always there waiting to bloom if water gets in or biocide is forgotten. As said, I've not had a problem in the 6 seasons since using this method. I've never seen any water or bug in the plastic reservoir below the filter, for example.
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If you are using additive - the dead bug which is the problem will be broken down and pass through to be burnt in engine ... its why I strongly advise Enzyme based Biocide. I really advise against additive that just kills it - that type is used when you can let fuel stand and settle. Unfortunately some of the additives sold are only kill agents. I'm not going to name - so please don't ask.

6 seasons ..... Back about 12 years ago - I sectioned of about 400litres of 'expired retention' samples of Heating Oil / FOD40 / FOD49 .... all grades of Gasoil (diesel to you lot). FOD40 is French standard Fishing Boat stguff ... FOD49 is Road Vehicle grade .. the 40 and 49 being the Cetane number for anyone interested. The samples are usually to b e held for at least 90 days after loading out. All loadings out were tested and passed quality specs. When samples expired - I decided to supplement my boats usage.
I have a pump and filter system far finer than any I have read about on forums such as this. Its setup to take from one 200lt barrel and into other 200lt barrels. Process can be reversed etc.
All the samples were emptied into barrels (2 ) .... due to evidence of wax ... filtering was done and samples taken for test. Fuel was on spec. ... tripping the lower Cetane limit but passed.
I used that fuel based on a 50-50 mix with fresh forecourt ULSD (white diesel to you lot) .... and all fine for months. The mistake I made though was to bite me hard ............. later on cruise Swedish Islands through to Finland and home ..... I was hit by Bug !!

I ignored my own golden rule .... I failed to use the Biocide.

Once back on mooring ... I heavily dosed the fuel IN tank ... at that time I could only get Volvo Truck Additive as all stock we had was used .... Left it to work for a day. Syphoned out some via fuel line to dose the lines. Injection pump had to be passed to service to clean it out - that pesky thimble filter - inside. Then tank emptied using Pela .... fuel was stood in containers ... decanted of to clean containers leaving crud behind twice.
Dosed again ... left to settle again ... then decanted of to boat tank mixed with fresh fuel.

Bled system ..... started engine ....

Each year - I would estimate my 70lt tank is filled 3 - 4x if I don't cruise Baltic. I give maintenance dose of Bio which roughly equates to each 70lt throughput. I have to buy over counter now as I stopped industrial treatment ... too many companies undercutting now.
I change filters only when I remember .. and I can tell you - they come out looking pristine .....

My point being - that the CHEMICAL is the answer to keeping system running ....

Oh - those barrels ? I have about 150lts left and it provides fire starter fuel !!
 
Refueler said:
Not in a strop ... far from it in fact ...

My Post made point of blowing through lines etc. Once all fuel system is clear ... then a decent biocide treatment will break down any crud that is not 'vacuumed out' / settled in containers ... even any moisture left - which dead bug is like a sponge for.

I'm not so happy about this valve he mentions .... not unknown for valves to fail internally and lead to starvation. Also if tank is with plenty crud ... fuel pick-up can lead to intermittent / unreliable running .. eventually blocked lines.
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Which biocide wozld you recommend then? M16 is what I picked to kill the bastards.
 
DangerousPirate said:
I just ordered it, I didn't even receive the parcel yet. I am asking to find out if I maybe there is a better one obviously
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I know it sounds daft ... but I do not want to be drawn into which additive is better than another ..... years ago - a certain guy dealing tried to get me to lab test his - with hope it would endorse it. I declined obviously.
PBO / YBW did test it soon after along with others ....

The main point to remember is that each additive is designed primarily for an action. Plain Biocide just kills ... Enzymic breaks up the gunge / dead bug that causes the blockages.... as well as killing to a reasonable level.
 
Refueler said:
I know it sounds daft ... but I do not want to be drawn into which additive is better than another ..... years ago - a certain guy dealing tried to get me to lab test his - with hope it would endorse it. I declined obviously.
PBO / YBW did test it soon after along with others ....

The main point to remember is that each additive is designed primarily for an action. Plain Biocide just kills ... Enzymic breaks up the gunge / dead bug that causes the blockages.... as well as killing to a reasonable level.
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Do you have an example for enzymic then? I'll try that before I try m16 then.
 
DangerousPirate said:
Do you have an example for enzymic then? I'll try that before I try m16 then.
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This is the test report made ny PBQ all those years ago ... note that Soltron is no longer on market - substitute Startron - which Soltron copied.

Note that the explanation of bugs and what happens in tank has moved on from that report .... SRB's as example were not addressed.

The usual industry test is to actually incubate samples - which then covers ALL micro organisms that can affect fuel. But that takes days ...
 
Poey50 said:
I had a bad dose of bug that came free with the boat on purchase in 2016 since she hadn't been used for about 18 months. Our tank is also very tricky to move so I haven't!

I built a fuel polisher and use this at the start and end of every season. I also dose every batch with Marine 16 and am scrupulous about sealing the fuel cap threads with soft grease to avoid water getting in. Tank condensation has been demonstrated to be a myth so I don't bother filling before layup. I've never had any problem since.

suZ02jhl.jpg
Click to expand...
Condensation is definitely not a myth, we get a lot of it..
But the picture looks familiar, the only difference to mine, is before the pump and filter the hose drops to a glass demi John, this allows water / bug sludge to settle out and reduces the consumption of filters...
When ever I'm working on the motor boat I connect it up, with a copper tube down to the bottom of the tank, and a return rubber tube . Hopefully the copper will cause death to the bug as well, as copper is a killer to most forms of life.
I've a bottle of some chemical to add to the tank on each fuelling, but it's been I while since I first bought it and can't remember what it is.
 
Rubbish..
I lived in Saudi for a few years, near the coast, high humidity , cars there rusted in the body above the doors, along the roof edge, how else would that rust occur but condensation?
My car this morning, condensation on the inside of the windows. Same as getting condensation on the inside of the tanks..
He counts the amount of water from one condensation cycle, my motorboat is in the water 365 days a year, ok you won't get condensation every night but you will get a lot of nights and it will add up..
 
The Q said:
Rubbish..
I lived in Saudi for a few years, near the coast, high humidity , cars there rusted in the body above the doors, along the roof edge, how else would that rust occur but condensation?
My car this morning, condensation on the inside of the windows. Same as getting condensation on the inside of the tanks..
He counts the amount of water from one condensation cycle, my motorboat is in the water 365 days a year, ok you won't get condensation every night but you will get a lot of nights and it will add up..
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Maybe read the Rod Collins (Marinehowto) article and explain how, for several years, in high humidity circumstances, his experiment to test the condensation theory has a tank that remained bone-dry.
 
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In my admittedly brief search about enzyme biocides everywhere I looked I saw warnings about damage to moderen (esp. common-rail) engines and the fact that enzymes merely inhibit the bug, whereas the biocide kills it. Nowhere did I find reference to it breaking down the deposits so the engine can swallow them.

I'd think really carefully about the implications of not emptying and cleaning the tank and fuel delivery system while you have the chance as the risks of leaving gunk in place is exactly what you are trying to avoid. Will you ever have confidence in your fuel supply in a rough sea agan if you don't?
How much effort you take to save the existing fuel depends on how much it's value matters to you but a simple polishing rig with a CAV type filter and sheap ebay pump and hoses should be doable for fifty quid. A hundred litres might tempt me, but less...? Mind, make the rig up neatly and it'll sell on ebay aftewards.

You will always be dosing with biocide at every fillup from now on and that plus a clean tank to start with should afford you the confdence you need.
Never leaving the tank more empty than you have to also helps reduce moisture ingress. I left my boat in Turkey chock full for 6-8 months at a time with no probelmfor 8 years until one year I got lazy and left it over winter ⅓ full. Result? A tankfull of jelly. Co-incidence? Maybe. Maybe not, bit it fits the dialogue.

I'd be very reluctant indeed about using neat biocide in any way - it's nasty stuff - read the labels. It'll work as it's suposed to so according to the instructions so inventing off-the-wall techniques like using it neat probably isn't a wise, let alone a safe move.

You've got two ways to do this, properly or otherwise. It's your choice!
 
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Slowboat35 said:
In my admittedly brief search about enzyme biocides everywhere I looked I saw warnings about damage to moderen (esp. common-rail) engines and the fact that enzymes merely inhibit the bug, whereas the biocide kills it. Nowhere did I find reference to it breaking down the deposits so the engine can swallow them.

I'd think really carefully about the implications of not emptying and cleaning the tank and fuel delivery system while you have the chance as the risks of leaving gunk in place is exactly what you are trying to avoid. Will you ever have confidence in your fuel supply in a rough sea agan if you don't?
How much effort you take to save the existing fuel depends on how much it's value matters to you but a simple polishing rig with a CAV type filter and sheap ebay pump and hoses should be doable for fifty quid. A hundred litres might tempt me, but less...? Mind, make the rig up neatly and it'll sell on ebay aftewards.

You will always be dosing with biocide at every fillup from now on and that plus a clean tank to start with should afford you the confdence you need.
Never leaving the tank more empty than you have to also helps reduce moisture ingress. I left my boat in Turkey chock full for 6-8 months at a time with no probelmfor 8 years until one year I got lazy and left it over winter ⅓ full. Result? A tankfull of jelly. Co-incidence? Maybe. Maybe not, bit it fits the dialogue.

I'd be very reluctant indeed about using neat biocide in any way - it's nasty stuff - read the labels. It'll work as it's suposed to so according to the instructions so inventing off-the-wall techniques like using it neat probably isn't a wise, let alone a safe move.

You've got two ways to do this, properly or otherwise. It's your choice!
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So in essence biocide is useless and I have to take the engine out, get the tank out, cut it open, clean it and reassemble everything?

I try my method first because it is by far cheaper. And the Isopropyl alcohol should kill and dissolve the slug
 
Blimey its hard work ...

The objective is to get pipes / filter case / tank as clean as possible of gunge .... to dose the fuel to keep system functioning. How each individual does it depends on tank accessibility etc.

A comment has been made about neat additive ..... Volvo provide for 'Trucks' additive when bug is found ... the instructions when I obtained it from local Volvo Truck Service - usual steps of add to tank ... empty tank ... blow lines etc. then to have new fliter + fill filter with it and start engine.

As to gunge and water broken down to pass and burn in engine .... the amounts in the fuel will not harm the engine ...
To mention Common Rail - reminds of Mercedes rubbish when they were advising against ULSD ......

Ask yourself this : If you use a Kill chemical - what are you going to do with all that dead bug that collects each time you fill up ?

Once you have a clean system that's functioning and bug is under control - a Kill / Enzyme type additive will allow you to keep reasonably clean system with minimal gunge collection.
 
My experience with the "bug" is that the crud in the tank is gelatenous. It clings to the pipes, gums up the injectors, blocked the filters and can even gunge up the mechanical pumps (Don't even think what it can do to a more modern common rail system). The gel will sink to the lowest part of the tank. this will render your drain valve inoperable. It also clings to the surfaces of the tank. It's mostly dead cells and bug crap but unless you get it all out (Steam cleaning is best) dosing future fuel loads with biocide is not a complete answer. There will be a resurgence. The whole system needs to be cleaned. New filters are a must. I have had the injector and fuel pump (single cylinder 1GM10) serviced each time. I've also passed Methylated Spirits through all the fuel lines (a 100ml syringe from a horse vet worked well). Once you've sorted the system, then a drop of biocide or fuel treatment every fill will see you OK.
 
As said, I think the emphasis on trying to eliminate the microbes that, under certain circumstances, cause diesel bug outbreaks is misguided. A scrupulously cleaned tank is likely to have more microbes as soon as the next fuel is added. Rather than eliminating the microbes, denying them the conditions that allow them to flourish seems to me the correct approach and that means removing water, not from condensation (another popular sailing myth) but from water ingress at the cap and the hygroscopic nature of diesel itself. I run down the tank before layup so there is then less diesel to absorb water over winter, I add soft grease to the filler cap threads every time I remove it, I add Marine 16 at every filling, and I fuel-polish (remove water and any bug in the inch below the take-off point) twice per year. Despite buying the boat with serious contamination, that is all I have done - the tank was not cleaned - and I have had no problems in the 6 seasons since, despite some rough conditions that usually stir things up.
 
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DangerousPirate said:
Generally asking as it confuses me a bit: Does fuel polishing clean the bottom of the tank, too?
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I’ve never seen the inside of my tank so I can’t say for sure, but the intake hose for the fuel polisher (photo above- but hoses not shown) goes below the fuel outlet spigot and is long enough to reach the furthest parts of the bottom of the tank. During normal running of the engine there is some natural polishing since the return hose sends back clean diesel. But unless there are lumpy conditions it is the area below the level of the outlet spigot where water / bug gathers and which polishing is targeted at.

I simply blindly move the hose position around if not finding any water / bug and, when there is some in the sight-glass, I keep polishing until there is no more. Over maybe an hour I cover all of the bottom of the tank several times until I can’t find any more. It’s possible that moving the hose dislodges stuff but I have no evidence for that. It seems to suck up very easily and seems to gather from a reasonable area around the end of the hose judging by how far I have to move the hose to find a new batch. There is never any blocking and, TBH, it’s quite rare to find any now, so perversely, I quite enjoy finding some and catching it. Don’t judge me.

The long hose (that goes to the bottom of the tank) takes fuel to the right hand hosetail in the photo so the pump draws fuel through the filter. The return hose is shorter - just long enough to be pushed down into the filler cap next to the long hose. There needs to be a reasonable depth of fuel in the tank for the pump to work and depending on how deep I sometimes have to prime the filter (top up with diesel). Does any bug stay adhered to the wall of the tank? Possibly, or even probably, but if I can't dislodge it with the filtering then experience after 6 years is that it isn't going to cause any trouble. But the bug lives in water and that is eminently suckable. It first appears in the sight-glass as gobbets of soft black slime but then sinks to the bottom forming a level black watery base to the glass with all the diesel separated above.

Apart from occasionally moving the intake hose, little monitoring is needed so I'm generally pottering around doing other things and simply check back from time to time. It's an enjoyable job. The polisher stays on the boat just in case we have a terrible batch of fuel although this hasn't happened so far.
 
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