Diesel Bug

[mbird]

I've been adding Startron since last Autumn, so it's probably too early to tell if it's made any difference. I have had no running or starting problems since I cleaned the glow plugs, but I think for what it costs any older broads cruiser should probably be using some sort of additive. I have hel off changing the fuel filters for a few months to see if the additive causes any clumping to get stuck in the filters, so when I do change them I'll let you know if I find anything!

[mbird]

Hi All,

Just an update on the Diesel Bug situation.

I changed both fuel filters today on Tranquil Breeze, as it is 13 months since they were last done, and 6 months since I started adding the bug treatment. The fuel visible in the glass bowl of the water trap was looking a bit dark, but there was also a bit of water contamination at the bottom of the bowl. Upon removing the filter, I was presented with a load of slimy algea-looking gunk around the filter element. Obviously there is some bug contamination, but it was in strands rather than a mat, so I can only assume the treatment has helped to stop the filter clogging as we have had no running problems at all.

I'm glad to say it was only the first filter effected, and the second filter mounted on the engine was completely clean

Sorry I didn't get any photos, but I was covered in diesel at the time!

[andyfish]

For any kind of diesel contamination,or for cleaning the old system out we have always used diesel power plus made by a company called Millers oils based in brighouse,west yorkshire

should just mention I am talkling about cars and hgvs but should work same in boats

think its more to do with water getting into the fuel through condensation as opposed to anything biological that might want to grow in it, as diesel itself is a deturgent

andy

[Antares_9]

It is in fact biological Andy. The DIY test for it is in fact similar to a culture ish used for detecting bugs in the medical world. You are right about the water though, the contamination grows at the interface of the water / diesel and can be a real issue causing breakdowns from clogged filters in dangerous situations at sea. The reason it is not encountered in road vehicles is the same one as many other marine issues, lack of use or in this case lack of throughput. HGV’s rarely have the fuel in the tank very long at all and cars for not much longer whilst it is common for fuel to sit in a boat tank for months on end. I believe the product you allude to is a drier rather than an enzyme or biocide like those used by the military during mothballing and in the marine world.

[andyfish]

Is there any proof that this exists,cause in all fuel tanks there is fuel thats been there longer than the rest

andy

[pks1702]

Diesel bug is not a single species of microbe. It can comprise a collection of bacteria, yeasts and moulds. It can exist even in fuel that is quite clean, but at low levels. If it does not enjoy suitable conditions to enable it to flourish, there is little to worry about, as minor contamination will be filtered out as the fuel is drawn through to the engine.

'Suitable conditions' essentially means the presence of water, because the microbes live and multiply on a fuel/water interface. They live and reproduce in the water, but feed on the nutrients in the fuel. Given the presence of water, warm or humid conditions will also help them to propagate. The number of bugs required to pose a problem is many millions, so the level of contamination is measured as a logarithmic power in colony-forming units (CFUs). 'Clean' fuel will have a rating of up to a few thousand (2x103cfu/lt), light contamination which is enough to cause a problem is up to a couple of million (2x106cfu/lt), while heavy contamination will be up in the tens of millions (1x107cfu/lt).

[mbird]

It certainly exists in my tank Andy . The problem with river boats rather than lorries etc is the relatively small turnover of fuel (i.e. the tank isn't constantly being run down then refilled like a vehicle would), and so any contamination tends to build over a period of time. Add to that the naturally high humidity environment and a partially empty tank can create quite a lot of condensation. As David mentioned, it is within the water fuel interface that the microbes grow. Keeping the tank topped up will obviously reduce the surface area for condensation to form, which is why I tend to have my tanks filled every couple of trips.

I was a little sceptical like yourself, until I did the fuel filter changes a couple of weeks ago. I was very surprised by what I found in the first filter, as I mentioned in my earlier post, which looked like big lumps of algae - slimey and jellified. It was no where near bad enough to block the filter, and the second one was as clean as a whistle, but I can imagine filters that haven't been regularly maintained causing problems.

As to your point of fuel being a detergent, I am not so sure it is? Diesel is an oil (and therefore organic). When spilled in water, a slick forms on the water surface, which is dispersed by detergents (eg Fairy Liquid). If the fuel itself was a detergent would it not disperse on it's own? Having said that though, a detergent isn't anti-bacterial in it own right and so the microbes would still grow even if it was.

Me, I'm convinced, so I'll carry on adding the enzyme ...... just incase!

[Antares_9]

There is proof absolute Andy and there is plenty of research if you look on the internet and military research papers. As for the fuel remaining in tanks in road vehicles and plant it is usually relatively little and thoroughly stirred up and diluted to a high degree by fresh fuel on each fill.

It is possible to culture the bug for yourself in a petre dish if it is present in your fuel.

[andyfish]

point took,but how many of you have suffered with this problem?

andy

[Antares_9]

Me and Mike for two

[pks1702]

I am in the process of evaluating my winter experiment on the water/diesel interface

[andyfish]

Me and Mike for two

was it in a bit of a chop, ie stirring the fuel up

andy

[Antares_9]

No it was diesel bug in the filters, the kind of thing you mention usually only happens on older boats that have spent a long time on the rivers and then taken to sea not the other way around as was my case and in a boat I had owned from new though not the current one.

[andyfish]

It certainly exists in my tank Andy . The problem with river boats rather than lorries etc is the relatively small turnover of fuel (i.e. the tank isn't constantly being run down then refilled like a vehicle would), and so any contamination tends to build over a period of time. Add to that the naturally high humidity environment and a partially empty tank can create quite a lot of condensation. As David mentioned, it is within the water fuel interface that the microbes grow. Keeping the tank topped up will obviously reduce the surface area for condensation to form, which is why I tend to have my tanks filled every couple of trips.

I was a little sceptical like yourself, until I did the fuel filter changes a couple of weeks ago. I was very surprised by what I found in the first filter, as I mentioned in my earlier post, which looked like big lumps of algae - slimey and jellified. It was no where near bad enough to block the filter, and the second one was as clean as a whistle, but I can imagine filters that haven't been regularly maintained causing problems.

As to your point of fuel being a detergent, I am not so sure it is? Diesel is an oil (and therefore organic). When spilled in water, a slick forms on the water surface, which is dispersed by detergents (eg Fairy Liquid). If the fuel itself was a detergent would it not disperse on it's own? Having said that though, a detergent isn't anti-bacterial in it own right and so the microbes would still grow even if it was.

Me, I'm convinced, so I'll carry on adding the enzyme ...... just incase!

trust me diesel is a deturgent

[andyfish]

theres is no life- form that will live or grow in diesel

andy

[pks1702]

theres is no life- form that will live or grow in diesel

Come on Andy pay attention at the back

'Road Diesels' often contain a detergent element which allegedy assist in inhibiting injector deposits

[Happy Jax 3]

Diesel in it's raw state is not a detergent, it is a light based oil refined from crud.

However, during refining many additives are put in the mix and for sure detergents are added to assist in cleaning engine components and ensure clean running.

[andyfish]

Come on Andy pay attention at the back

'Road Diesels' often contain a detergent element which allegedy assist in inhibiting injector deposits

the fuel you use aint no different to what goes into cars or trucks

which rifinery makes this marine only diesel oil then,thats so inferior its cheaper and bug free

thought so!

andy

[Antares_9]

trust me diesel is a deturgent

A solvent, yes, a detergent no, a biocide absolutely not. Detergents are added to diesel but it is not in itself a detergent.

[andyfish]

how many of you have had your boat engine stop through diesel bug????

[jimbo]

Last time I changed my primeary filter something was in the fuel that came out of the filter casing? My best description of it would be it looked like squid ink mixed in the clean fuel? Not much of it but noticable all the same.

[Antares_9]

Firstly Andy there is no such animal as marine diesel it's just red as used in agriculture and plant and is different from ULSD sold to road outlets in that it contains (generaly) a higher sulpur content and has a lower cetane value whilst still conforming to EON.

[andyfish]

just tell me witch refinery it comes from and i will show my rear in harrods window!

ps

just been on my ADR refresher course and have consulted a 30 year expert on haz chems/fuels

andy

[Antares_9]

This might prove interesting reading for you Andy.

http://www.ybw.com/forums/showflat.php/Cat/0/Number/770105/an/0/page/26

[andyfish]

have you suffered with it?

cause the cynic in me thinks its booloks