Diesel Bug - fact or fiction

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snoozydude

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Gidday

I have a 20l diesel tank for a Yanma 1gm10. I was recently told to put in a diesel additive to stop deisel bug. I use the boat on a regular basis and run the engine about 1.5 hours a week.

Do I need a fuel additive?

What is the bug and the consequences of getting it?

Thanks in advance.
 
diesel bugs are actually several different organisms, but all have they same effect.

They are organisms which grow on the water/diesel interface. They are very 'slimy' and clog filters.

The best bet is to keep water out of the fuel tank, which is best done in winter/cold conditions, by filling the tank to the brim. No air filled spaces - no condensation - no water in diesel.

If you are using every week, then you should have few problems unless you fill up from a tank/tanker/bowser which is already contaminated heavily.

Dosing continually with biocides is not a great idea, as the bugs can develop tolerance to the biocide in the same way that bacteria in humans can develop antibiotic resistance.

Many forumites have used Soltron very effectively, though there is little scientific evidence provided by the several competing manufacturers/suppliers of how it works. It breaks down the slime by enzyme action into particles small enough to pass through fuel filters, and not being a biocide, it doesn't cause resistance effects.
 
Little scientific evidence?

Are you sure Brendan, surely you mean no scientific evidence? At least I've seen none in all the talk of solly although I will concede that it does seem to work.
 
a 20l tank is such a small amount and you use the boat on a regular basis so i wouldnt bother, i have a 35l tank and have never used the stuff as the tank gets filled every month.
 
Diesel Bug lives....
I got it once - nasty; engine seemed constipated and stopped. Changed filter and all was well.

Now I check the tank twice a season by using a Pela vacuum pump and an extension pipe to reach the lowest point of the tank. Since the first episode I haven't had a recurrence - and I buy my fuel from sources that many would consider "doubtful" as to quality.

Just check regularly and always carry spare filter(s). I use a primary and a secondary.
 
Dont forget, prevention is better than cure!! i have been on a boat that stopped every 40 mins for a filter change in a big sea - not very nice.
 
Diesel bug exists in ALL Diesel supplies.

Those that say one supplier is bad / another is good etc. are fooling themselves ........ sorry about that but true.

The bug comes in various forms and is NOT just simply an Oil / water interface item. It depends on which bug.

There are bugs that survive on sulphur IN the diesel, without water, there are those that use the oil / water interface, there are those that stay in the interface.

Evidence of bug contamination starts with brown / dark 'gunge' settling in bottom of tank - this is DEAD organisms ..... and is actually the problem that stops engines by clogging filters. The LIVE bug is not so much a problem.

There are various chemicals on the market that a) kill the bug, but leave residues, b) kill the bug and dissolve the residues, c) 'eat' the bug / residues and break it down to manageable microscopic size.

Ok on to my point of supplies etc. - the condition of suppliers tank is not so critical actually - many a farmers tank looking like a relic from some War arena is fine, with some pristine clean looking high-street tanks being badly contaminated. Outside condition is only a cosmetic affair. The main point is that the tank contents are regularly changed by useage.

For a boat with a 20l tank .... I wouldn't think that there should be a problem, and the size of tank makes it easier to lift out, swill out and keep clean - I would presume.

I do not say ignore the Chemical guys .... but really it is a matter of sensible husbandry and regular darining of bottom of tank to ensure that no build up of sediments occurs.

I repeat again for those who do not believe - ALL diesel has bugs in it - unless it has just immediately prior been dosed for bugs .........

IF you do use an additive .......... use it sensibly and do not overdo it .... once in a while to keep things sorted should be enough....... if at all with such a small tank.

The postee that siphons tank bottom out is actually doing one of the best actions he can .... as he can have bugs, but they will not clog his filters with dead crud. He is also not adding to the environmental accumulation of chemicals etc.

Me - I have an approx. 80ltr tank that sits month after month with diesel in, often only half full ............. as yet I have had no problem after 6 yrs.......................... I buy from cheapest source I can find, I even do not filter into the tank ......
Yep - I run Petroleum labs, inspect 1000's tons of the stuff and I do not take my own advice !!!!

/forums/images/graemlins/tongue.gif
 
I am over from the dark side (mobo) but my experience of the Bug may prove useful. I bought a new boat in February 2002 which had a 300 lt diesel tank, after approx 50 hours of running and halfway across Bigbury bay enroute to Salcombe from Plymouth we started to lose engine power and revs, we returned to Plymouth, with max speed down to 7 knts from 24 and rpm down to 1100 from 3400. On getting back on our berth i changed the primary filter which improved the situation but did not cure it completely, I then attempted to change the fine engine filter which put the situation back to where it should have been. I then had the tank drained, taken out and steam cleaned. then 6 months later, I sold the boat and bought a new one, this time much bigger and with 2x500 lt tanks.
as you can imagine I did not want a repeat of the original problem, so I kept the tanks full and used a biocide treatment, guess what?
Correct! both tanks contaminated. I religiously check the primary filter and found that the lower half of the bowl contained a green moss like substance. This was about 6 months ago. I dosed heavily with Soltron and i have replaced the primary filters every 10 hours of running and although the filters are dirty I have experienced no running problems at all.
my advice is to use Soltron as a precautionary measure. Although expensive, it is cheaper in the long run, and the size of your tank it will not be prohibitivly so.
 
Re: Diesel Bug - Prevent it or Cure It

The Bugs exist - had over 5,000 tons of diesel get the bug and rejected by the Navy after we had hauled it all the way from Grangemouth to Falklands, so we took it back to bonny Scotland and pumped it into the hillside at Campeltown in Scotland where presumably it still is!!

I like to prevent rather than cure so always keep my tank full as possible and drained of any condensation. After 10 years with present boat no signs of bugs.

Guess the treatments do work but what happens if yon bugs mutate and start feeding on the treatment? Experience tells us it will happen one day.

They must be happy little bugs however they certainly breed well!!

Brian
 
Re: Diesel Bug - Prevent it or Cure It

Dug,
I'm with Nigel on this one. I use an additive but not every tank. I also vary the brand and type. There is a Queensland company that makes a good product, the name escapes me at the moment but its regularly advertised in Traderboat. It also removes the glazing off bores.
 
Re: Diesel Bug - Prevent it or Cure It

My recent experiences (FWTW) suggest that prevention is nigh on impossible, and that filters may be too late.
A couple of years ago I had the tell-tale symptoms - engine stuttering and stopping, mid-Alderney Race and very bouncy. New filters did the trick, Fuel-Set 'seemed' to cure the problem, as nothing happened until this season. Off Guernsey, and uptide of the Casquets, minimal wind but bouncy seas, it happened again. Change of filter didn't quite do it. I disconnected the fuel line and applied suction (mechanical, not oral!!) and released a load of crud. Back in business. Last week the same again, between Poole and Hurst, same conditions - had to apply quite firm suction, nothing came (empty tank, I asked myself?) then suddenly loads more crud which had jammed in the fuel line between tank and primary filter.
A friend, expert in oil tanks and pipelines, confirmed what Nigel says - some bugs live off the sulphur and the hydrocarbons - water is not an essential, and indeed sampling from the drain-cock shows no water in the tank. The Fuel-Set should anyway disperse the water. However, sucking up samples from near the bottom, after stirring the fuel round, brings up quite a lot of crud.
Question - how to stop it getting into, and blocking, the fuel line? I could get the tank emptied, cleaned etc. but all experience seems to show that it will recur.
So, my plan is to install a readily switchable suction system to be able to quickly draw any crud out of the fuel line, at regular intervals, or under way if it happens again.

Brian
 
Possibilities ....

The fuel draw line in a tank often is a pipe vertically down into tank and end just a touch above tank bottom. so what to do ?
Well you could solder on a U to this and have the end open Upwards instead of sucking of the 'floor'. In fact you could place a small filter on the end such as you have in most older petrol tanks. But this will necessarily be not so fine to stop real small stuff.

If the tank cannot be lifted out or easily moved - then a stir is often not enough ... you need a low pressure air hose OR believe it or not .... a paint stirrer on a drill to really get the contents stirred up. Get it really stirred up while syphoning of the tank .... as most contents if you stir up and then syphon will have started to drop out again.

OK - so now you have a load of diesel with loads of crud in ... so ? Let it settle, doesn't actually take too long. Then filter into another container.

Now using a cut down mop .... start mopping out the bottom of the tank to get last vestiges of crud out.

Once done .... then dose down your fuel you emptied out with your favourite concoction and let it stand again for a bit .... to let any bugs that now die settle out !! then filter into the tank. The additive you have in the fuel should put to bed any bug left in the tank, the fuel should be reasonably clean and you should have a sweeter life.

Honestly - filter and additive in buggy fuel is enough to satisfy most situations and not necessary to throw away the fuel - unless you wish to donate to Luther Charity !!!

Of course you can go with Soltron or other stuff that purports to eat the stuff .... but at end of day - isn't it nice to have a clean tank ????

Episode 2 later !!!!! (only joking !!) /forums/images/graemlins/grin.gif
 
Re: Possibilities ....

Some good ideas there - the problem is getting the fuel draw-pipe out, I think it may be welded in place but will need to check. A fine filter on the end would mean having to get it out & clean it regularly.
Another idea is to set up a pump to suck up the fuel (there are 350L. in my tank....) into a large clear reservoir (camping water storage container or similar, with an exit pipe about half-way up, draining back into the main tank - leave it running for a few hours, with occasional stirring of tank, allowing the crud to settle to the bottom of the clear plastic reservoir. Perhaps even do it through a 'primary'-type filter. There's no way the tank can be removed - would require major surgery to the stern of the boat (Fisher 34); and only a 2-inch-dia access hole where the fuel sensor usually goes. I believe this 'recycling' technique is available commercially but is probably expensive. Has anyone any experience of this?

Brian
 
Re: Possibilities ....

Forumite Boatone on the Mobo forum made a DIY kit with pump and filters plus hoses to do this very successfully, all mounted on a plank of wood I seem to remember
 
Re: Possibilities ....

LVM ..... make a 12v submersible pump .... last one I bought was about 14 quid. It pumps diesel or water ....

I wonder whether a filter could be put in the line so pump out and back to tank ... the filter taking the crud out .... but then again if crud is excessive ... then filter will soon be overwhelmed.
 
Re: Possibilities ....

Yes, the filter would surely get clogged - hence my suggestion of a sizeable reservoir, with the crud settling, and the drain-off, back to the tank, taken from well above the crud level. Observing cruddy samples in a clear plastic bottle shows that it settles very quickly, like a black snow-storm, when shaken. The fine particles will not be a problem, as they are either stopped by your usual primary filter (could choose a finer filter-size e.g. 10 micron instead of my usual 30) or are 'consumèd in the mighty fire' of four cylinders....

Brian
 
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