Diesel Bug.

Quest

Quest

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Is there a way of protecting against diesel bug by using some kind of fuel additive to prevent it?

If not, what is the accepted method of dealing with it if your fuel tank Is affected?

I've heard/read somewhere that keeping fuel tanks brim full is a protection of sorts, is this correct?

Not currently affected, but looking at an upgrade to a diesel boat and thinking thro the issues.

Thanks,

Andrew:confused:
 
Quest said:
Is there a way of protecting against diesel bug by using some kind of fuel additive to prevent it?

If not, what is the accepted method of dealing with it if your fuel tank Is affected?

I've heard/read somewhere that keeping fuel tanks brim full is a protection of sorts, is this correct?

Not currently affected, but looking at an upgrade to a diesel boat and thinking thro the issues.

Thanks,

Andrew:confused:
Click to expand...

Get your tank treated with an addatives immediately, people often think that just because they haven't had it they don't need to worry, treat your fuel every time you fill up,mdont take the chance!

Leaving your tanks full over winter is advised, it leaves less room for condensation in the tank.

There are lots of products on the shelf from all chandlers, I use Exorcet anti bug, and Exorcet fuel store plus, and am very pleased with the results so far
 
The bug grows in the water from condensation or poor quality / badly stored fuel, and you never know what your going to get. The bug feeds on the fuel, so lives at the interface between the water and fuel.

As the bacteria die they build up a black sludgy substance that can block fuel lines and filters. Also excess water entering the fuel system can damage delicate fuel injection pump parts, so keeping the free water in the fuel to a minimum is the trick.

Remedies ...

1 Additives that breakdown the water into the fuel, e.g. Fuelset, or that kill the bug. Some claim to breakdown the sludge, but if you have enough sludge present to block a filter then you need to sort the problem out, as fuel treatments alone won't do it.

2 Keeping your tank full will reduce the air space within the tank, so less airborne condensation, but if you have large tanks you will waste fuel due to excess boat load whilst carrying it around on short journeys. My boat looses 1.5 knots with full tanks, or at lower speeds fuel consumption increases markedly.

(Do not go on a journey with barely enough fuel - you never know when you are going to get caught out - I always have at least twice the fuel required for any voyage).

3 Polish the fuel. I have a simple set up with a Baldwin Water Separator / 30 micron filter, feeding to a 12v fuel pump, all moiuted on a portable carry frame. This can be used with a simple dip tube into the tank, or from a low level draw off, with the return back into the same feed point.

I am installing a fixed system into my Fairline that will tap off from each fuel tank low drain and return via the engine bleed offs.

Running the pump for a couple of hours whilst drawing off the bottom of the tank will collect a great deal of the more contaminated fuel (the sludge and water are heavier than the fuel so gather towards the bottom), but you need to rock the boat to move the fuel around.

4 Ensure you have decent Fuel / water separator pre-fitlers, e.g. Racor on the feed line to the engine. I prefer the ones with the clear bowls because you can see if there is an accumulation of water, but the BSS for instance do not like these. Fortunately I am on sea water so the BSS scheme does not apply.

5 If you have serious volumes of sludge then the tank needs to be cleaned out. If access to the tank is limited then this can be difficult, in which case perseverance is needed. Empty the tank leaving a trace level at the bottom, then use an electric pump with decent suction such as a whale gulper discharging to empty drums. Use a narrow flexible tube that can pick up around the base of the tank, but several refills of filtered fuel may be needed to get the worse of the sludge out.

Some recommend steam cleaning, but this will leave water present at the end of the process, and this is the thing you are trying most top avoid.

Good luck.
 
Quest said:
Very informative, thanks.

If fuel is treated diligently every time you refill, is this close to a guarantee against the problem?

In No. 4 What does BSS refer to?

Thanks,

Andrew
Click to expand...


Good advice given by superheat6K.

The BSS stands for Boat Safety Scheme. It is a bit like an MOT for boats on the inland waterways. It has to be re-newed every 4 years. One of the criteria is that clear bowls on the fuel pre-filters are not allowed, have to use metal bowls instead (i believe flame deflector heat shields can be used to protect said plastic bowls) incase there was an engine room fire, idea being metal bowl being more fire resistant.
Personally i don't like the rule, but you have to obide by it to get the BSS.
 
Yep - superheat6k seems to have covered the points.

We identified the fuel bug about 100 miles from the nearest land when one of our engined complained of low pressure fuel. We always carry a load of spares so we could have limped home but in fact our fuel system is fitted with duplex prefilters and it turned out to be a simple matter of switching over to the backup filter in the set.

When we got back to our home berth, the problem wasn't as bad as we had feared - On our boat, Princess had designed small sumps with drain off valves into the fuel tanks. The bug grows where the water is and these sumps are designed to collect any water from the fuel so it turned out that all we had to do was to drain the contaminated fuel from the sumps and then treat the remaining fuel with a strong mix of biocide. - we used Marine 16 which worked well and after about 72 hours there was no trace of the bug.
We also used a small pump to circulate the strong fuel mix around the system. At the time the tanks were only a third full so this meant removing the tank inspection hatches and spraying the strong fuel mix around all the places we could reach inside the tanks.
I did buy a cheap Raycor filter from Ebay to put inline with the pump but our bug problem turned out to be not as serious as we origionally thought.
I did a short write up that was published in MBY in the March 2012 issue.

Since then, we left the boat over the winter with full tanks containing Marine 16's complete treatment. Although expensive, I understand that this complete treatment contains lubricants for pumps and injectors etc.

At each fill now, we just use the standard Marine 16 bug treatment which seems to me to be the best value. As superheat6k says above there are two methods of treatment - one which removes any water in the fuel (Fuelset is an example) and one that kills any bug in the fuel (Marine 16 / Grotamar are examples).

In Spain where we keep the boat, they have switched the marine fuel to ULSD road fuel. This means that the fuel is low in sulphur and also has some biodiesel mixed in. IMO this is a recipe that the bug likes - the sulphur used to keep the bug at bay and the biodiesel seems to me to encourage growth.

My advice though is DEFINATELY treat your fuel.
 
Do you have a problem at the moment?

The first thing you need to do is regularly remove water from your fuel tanks, easier said than done in some production boats. Some boats have sumps and drains or stripping lines , get to know your fuel system.

Personally I use a stright biocide Grotamar 82 which is a well respected product this kills diesel bug which in a preventative situation rather than a contaminated system means it will collect dead bug in your prefilters.

http://www.echamicrobiology.co.uk/shop/grotamar®82/3,16,0,0/default.aspx

Sorry you will have to copy and paste the link I cant do active links.

One litre about £34 will treat 4000 litres of fuel as a preventative, you would use a stronger solution in case of contamination.

I dont like the idea of some fuel treatments that disssolve the water into the diesel, i want to keep it as far away from my engines as possible.

Treating a heavyily contaminated system is another matter.
 
Thanks Gents.

No, I don't have a problem at the moment. Current boat with petrol outboard is up for sale. Looking at making a change to diesel inboards and have seen a 'maybe' option. Heard a bit about diesel bug bt still had a few questions, which you have all been kind enough to help clarify for me.

This forum works wonderfully when you want to tap into others experience and knowledge.

Thanks again,

Andrew:)
 
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