Diesel bug - anyone with experience?

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tillergirl

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Doing the annual change of fuel filters yesterday, found that the primary filter had diesel bug crud in it. It was far from choked but nevertheless clearly there. Bowl was completely clean and the secondary filter was spotless.

Question is: do I shock the system or just add a preventative level of treatment? If I shock the system, how long before I should change the filter (I've bought some Grotamar 82)?
 
Hi

You need to have a good look at the tank as well as the filters. I had a minor problem, and transferred all the fuel out to cans, and filtered it back. Big dollop of treatment and fingers crossed. Its been OK so far.

The instructions are usually pretty foolproof. Shock the system, and check the filters again after a few hours of running.

Regards

Ian
 
Instructions with the Grotamar are pretty well non-existent! Taking all the fuel out on the mooring is going to be a bit of a problem but I can lift the inspection hatch easily enough. Thanks
 
I have also experienced the dreaded bug.

I drained the tank, put in appx one gallon of petrol and left if for two days in the hope that it would help break-down whatever was in there. Drained the mucky petrol, left the tank open for a day to evaporate any residue, filtered the original diesel back in to the tank and then shocked the system as per instructions. This must have done some good but it did not cure the problem.

The best advice I can give - based on practical rather than technical experience - is to keep a supply of filters on board and change them frequently. Chandlers are charging appx £6 per filter but the nice people at https://inlinefilters.co.uk/ are much cheaper.

It will be interesting to see what others have to say.

btw: I have only used red diesel on one occassion, the rest of the time I have filled the tank with road fuel.
 
Thanks. I have a stock of filters ready! Always red diesel and in recent times all from Bradwell. I am wondering if I can shock the system sufficiently to get through the season and tackle draining down as the first thing to do on laying up - bit early to be talking about that but in fact it is all booked up for 6th November! Last time I drained down the tank was 1992 I think.
 
Wouldn't like to comment on the system shock aspect as I really don't know. Regular filter replacement is likely to be effective for this season. If you have a rough passage at any point, change the filter immediately after as this seems to be the highest risk time with the muck being loosened from the bottom of the tank.

When reading-up on this issue a couple of years ago I saw somewhere that on larger vessels they sometimes have to shovel the muck out of the tanks!
 
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I had a bug problem and tried various additives including shocking the system all worked to some degree but the problem kept reoccurring eventually I drained the system steamed the tank, flushed it and junked the red diesel from the tank. I then filled up with white usually purchased from Mr Tesco and kept the system topped up. Not the easiest of options but it cured the problem and was worth it! no more changing filters at 2.00am in a lumpy sea followed by bleeding the system.
 
Thanks for those extra comments. Definitely a full clean up this winter if I can get that far. I am fortunate with two good sized inspection hatches so, having done it before I know I can get the tank spotless. I'll see how far I get before trouble emerges. I guess it's quite easy to check on the primary filter every so often.
 
Drain the fuel. One of those electric drill pumps work quite well. Open the tank up and clean it out. Don't forget to clean the fuel line from the tank to the primary filters. Filter the old fuel several times with home made fuel polishing rig before returning to the tank. Fit new primary and engine filters.

OK a real faff, but the only satisfactory method.
 
Yes, I shall do that; indeed I think I might fit a self-polishing kit on TG provided I can find room for the extra filter. My only question now really is whether I can get through the season without the major clean-up - which of course no-one can answer.
 
Access hatches are fine for me but the tank is in the saloon so the thought of the inevitable crud in a nicely cleaned start of season saloon is not attractive. I am hoping tomorrow to lift the smaller of the two hatches and have a peak inside.

FC, already bought some Grotamar 82, thanks.
 
The marine 16 treatment is supposed to good for breaking the crud down as well as killing the bug, I had to spend ages last year pumping through a fine filter from one tank to the other while rocking the boat from side to side to loosen the gunge in the tanks, finaly treated with an overdose of marine 16 and all seems ok (so far).
There was a treatment comparison test in PBO a while back and the marine 16 stuff seemed to come out very well.
 
I had a bit of a nightmare over the winter with a split fuel tank. I needed to obviously empty the tank of 120l which i did with some difficulty but a rule bilge pump eventually made light of the job. The fuel looked very milky towards the end and I eventually found bits of tar like strings in the tank. I consulted Tony brooks who led the diesel course I completed a few years back and he confirmed heavy dose with Marine 16 then treat as per recommendations on the bottle. After the tank was reinstated i used about 40-60 litres of the treated fuel but the engine ran like a dog so added about the same of white diesel. the white apparently burns at a higher temp and since the Marine 16 had absorbed any water in the mix wouldnt do it any harm. problem solved and has been running well touch wood ever since. I then topped up with more white. I posted a few pics on my blog http://orcanasigma38.wordpress.com see diesel bug post. The in line water separator was thick with milky bug too so that got a good clean out too.
a very messy and smelly job but glad i was able to complete. use the Marine 16 now as a fuel treatment which is i believe favoured by the RNLI. I used to use fuelset but Tony suggested that given the biofuel % it was not as effective.
Good job done but even though i had the tank out etc it seems this could be a once a year job from now on as good practice. I think I will see and maybe every other year.
Ben
 
urm.... its blue!

P1000697.jpg


Seriously, not sure I completely understand what I am seeing, but if your reference is to the slime on the bit being held up (fuel tank sender?), then its nowhere near as bad as mine was, so it could be a lot worse!
 
To be honest I am not sure what I am looking at either. When I was looking with my eye, I could not see those red bits so I assumed that looking down into the tank without any direct light the red diesel looked opaque. However, it looks to me looking at the image that there is a layer of crud on the bottom. The crud on the bit you can see (part of the gauge float assembly) is minimal. I've 'shocked it so I'll have another look on Monday and see what has happened. I suppose I could try and hoover up the crud layer on the bottom?
 
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