Diesel bug - anyone with experience?

The light reflecting off the tank is a little distracting as I found with ours. We had a stainless tank and the fuel looked milky but only until the fuel had been cleaned and fresh put in that we realised how off colour the fuel had been. I would pump out the tank as you have the hatch off and then clean the crud out.
 
removed fuel, cleaned and bleached tank, 1000ltr white diesel, was in NL then. 12 mths later, still got bug.

It is the low sulphur bio effect. How soon before somebody dies because of this euro regulation ****.
 
david_bagshaw said:
removed fuel, cleaned and bleached tank, 1000ltr white diesel, was in NL then. 12 mths later, still got bug.

It is the low sulphur bio effect. How soon before somebody dies because of this euro regulation ****.
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Good point. I was thinking last night of a time I dropped my sails off Calais in front of the sea wall in n on-shore wind. Engine packing up then would have been catastrophic! Currently in a dilemma. I know I should clean it up but Monday is looking good for surveying the SW Sunk but I won't have time to do that before I go!
 
So how can I tell if I have it?

Own up time; I bought my current boat 4yrs ago. Each year I have replaced the fine fuel filter(which has always been in good condition), but not the primary, water seperator filter until this year. You will see from below that it was disgusting, but can anyone confirm that it shows signs of the bug?

My engine a Yanmar 2GM20 is paricularly frugal, so in 4yrs, I have used less than 200ltrs of fuel and as a result it has been brought from petrol stations in cans, so I would suspect that it has been in better condition than from fuel pontoons.

After reading the above, it is my intention to use Marine 16 on the fuel, and I expect to give it a shock. Any thoughts if this could cause any issues?

 
Mine didn't look like that. It had a few black strands. It was far from being blocked and I don't think yours is near blocking either although you have more crud than I had. Is yours after having dried out a bit? Personally I would say you have it. The first 20 years of changing my primary filter I saw nothing in it at all.
 
Yikes that is a scary photo! However better for being sorted!
When we heavily dosed with Marine 16 because it absorbs the water in the fuel and this is precisely the interface for bug to thrive and prosper it made running of the engine very doggish. However i diluted the treated fuel with fresh white and as if by magic the engine is running well. The Volspec engineer was looking at possible injector problems prior to some fresh going in. Once the mix was established the problems disappeared.
So my advice would be clear everything you can of obvious bug slime including tank, filters etc, treat heavily but in line with dose recommendations Marine 16, then add some fresh white as it burns at a higher temp to finish. Use Marine 16 then as a preventative dose under normal circumstances.
Our water separator was thick with milky stringy gunk - not quite as crusted as yours appears to be.
 
My advice would be to panic later!

Our filter clogged last year while punching through some rough water with a largely empty tank. Limped home with only low revs available, Changed filter (obvious goo inside), and had the same problem again soon after. Nervously recalling all the horror stories of diesel bug from this forum and elsewhere, I set about draining the tank (into a large collection of transparent 2 litre mineral water bottles). I was surprised when the first fuel came out lovely and clear (was all red diesel, and mainly of some antiquity as our motor uses little fuel). I was even more surprised this continued to very near the botom of the tank. The very last dregs of the tank were clear too, but with just a few small bits each of hard crud and gloopy stuff. I refilled with fresh fuel and its all been fine since.
 
Yes that is bug.

Of course modern filters have the special coating to trap water, so of course the bug thrives on the filter! as well as in the tank.

every body talks about bit growing on the water at the bottom of the tank, but even when the tank sides are sloped the bug manages tio stick and grow there. This is why I do the bleach wash, as only a little bit needs to be lefft behind and it all starts again.
 
I shall see how far I get tomorrow as I try to survey the SW Sunk. Winds are forecast for easterly so it will be a motor out there - well at least to the east of the Barrow. If it all clogs, it's a downhill sail all the way back but I have spare filters to change as well.

I fancy an ASAP polishing system as part of a permanent system but at the moment am a bit stumped for where to stick the Racor filter so I can get at it.
 
A friend had a bug problem last season. Chatting to him the other day he was telling me about his plan to install a 'switchable' second primary filter such that he will always have a clean filter plumbed-in and ready to use at the flick of a switch, as it were.

Clearly, this is a good idea but I'm not sure whether it would overcome the need to bleed the system. If it doesn't, it's a simple enough procedure and much easier than having to change a filter in a lumpy sea.

Any thoughts?
 
My experience with the bug (among the fishing fleet off the Belgian coast :p) is that the replacement filter will block PDQ as well (within a minute or two). A third filter change was OK & got me in to Zeebrugge.

So, in my experience, a switchable second primary filter wouldn't have made any real difference.
 
I would like a switchable filter, but it would not have helped when a bit of **** blocked the uptake pipe. The vac gauge was still on 3/4 of full scale deflection after 10 mins with the engine off!! removed suction pipe at filter connected a rubber pipe and blew down it. fortunately it un bunged reassembled went for a re start with a full racor bowl engine ran and fortunately pulled the air through without cutting out. Thank god for twin engines as the other kept me going in a safe direction. was off the brisons at lands end at the time. (yesterday)

Tank was inspected and silt trap cleaned while port solent only 2 days before, after early signs of a filter blockage off beachy head & a preventative filter change shortly after.

Great day today seen a pod of 6 dolphins truly wonderful
 
Tradewinds said:
My experience with the bug (among the fishing fleet off the Belgian coast :p) is that the replacement filter will block PDQ as well (within a minute or two). A third filter change was OK & got me in to Zeebrugge.

So, in my experience, a switchable second primary filter wouldn't have made any real difference.
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I guess it depends on whether the bug presents itself in large gobs or smaller pieces. If there is a load of larger lumps in the tank and feed pipe then a second filter would block pretty-much straightaway as you say.

My experience - nowhere near the Belgian fishing fleet but just on the edge of one of the shipping lanes coming back from Gravelines - was one of a build-up of smaller particles. Changed the filter and the engine ran fine for 8 hours or so and then the new filter clogged.

Hoping for a bug-free season for all of us!
 
My princess came of the Thames and had been sitting with half emty tanks for two years.I used three set of filters from Penton Hook to the QE bridge.I tride all types of stuff until i read a post on the Motor Forum about Marine 16.I gave the tank three doses over about 3 months,that was six years ago I does the fuel once a year before the winter and have had no more probs.Marine 16 is the only one that worked for me
 
Undid the primary filter this morning and dropped it down a little to have a look. Spotlessly clean so I did it up again! Started the engine, expecting spluttering from air in the system etc and it ran perfectly. Tried it twice for 10 minutes each time - no problem with air which rather surprised (but also pleased) me.
 
Not sure how long I would expect to have to run the engine before dead bug clogs the filters? Perhaps I'll find out shortly.....

In tidying up, I found a half litre plastic container in which I had put the diesel drained from the primary filter bowl when I changed the filters a year ago. It has been sitting in a locker for a year. It was quite clear when I drained it off. Now it is slightly cloudy with a layer - not too thick - of black crud on the bottom. Container was sealed of course but was not full so there was air in there. But it shows the bug was there.
 
A few years back, my Wallas Cooker tank had black flakes in it. I bought some Fuel Set and massively overdosed the 5l tank with 5 ml (proper dosage is 10ml per 40l). The flakes dissolved and haven't come back. I did similar with the engine tank (86l) although not such an overdose, and this year had the first signs of black flakes again in the primary filter changed the filter after 10 hrs and it was clean...
 
I have been researching the possibility of putting in my own fuel polishing system - I would much rather prevent it than have this messing around - following ASAPs suggestions it would spend a good £270! There are issues also as to where I would put another filter (us wooden boats don't have loads of cavernous lockers). There is room in the heads which is adjacent if a little bizarre but I suppose I could hide the filter behind a neat iroko box........
 
Those of you who are using White roadside diesel, Beware.
This is from information received from a usually very reliable technical source.
Bio-diesel white mix is far more susceptible to the bug than red diesel.
There are increasing amounts of bio-diesel being added to normal road fuel.
This is to help with emissions, lower sulphur and cost.
Not an issue generally for road vehicles as you will probably re-fuel once a month at least.
However on a boat, especially a yacht, the fuel could be in there a long time.
I have been told that Tesco use a "B5" diesel which has a 5% bio-fuel blend.

In addition,
If you have a plastic tank where light can get to it there is a chance you can develop algae as well as the microbe bug.
The algae and microbe need water which they get mainly from condensation inside the tank and they grow in this transfer region between the fuel and water.
Treating the diesel will kill the bug but will not clear the grotty stuff so a flush and vigorous wash out is the only way to ensure a clean tank.

I delivered a Nauticat 33 the other day that had been sitting a ashore for some while.
The tank had been treated but not cleaned out.
After a bumpy trip all was fine until the next day when she wouldn't start.
On inspection the filter was blocked.
We were lucky it hadn't happened on entry to the harbour the day before.
 
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