Is this the diesel bug? (piccy)

[Mings74]

Hi all,
I finally put my one day diesel course to good use today, serviced my engine and replaced the impeller. (I'm a complete mechanical buffon). When I changed the water separator filter it looked like this!!!.

Amazingly the engine was running fine (Perkins 30hp 3 cyl Perama), although I've no idea how!. Is this normal sludge after one year, or is it the dreaded diesel bug?. Cheers Ming

 

[sailorman]

in a word /forums/images/graemlins/shocked.gif

 

[KenMcCulloch]

It looks very much like it. You don't say how many hours running this took, but you probably neeed to clean the water and bacterial sludge out of the bottom of your fuel tank. Refill with fresh diesel and add a good dose of some appropriate chemical.

 

[benlui]

Without a doubt diesel bug!!! No question there, looks exactly like I have seen on my own once too many times. I suggest you find a suitable diesel bug treatment to dose your tank and or drain it. I’m surprised your engine didn’t choke on it and stop?
I bet the very end of your fuel tank is full of that, get a pump with a hose to the end of the tank, and try to drain it and for the love of god, don’t run your engine when your tank is near empty, try to keep it above half full to avoid the bug being sucked up. If you are in a lumpy sea, it will also shake the bug around the tank causing it to contaminate your filters. After installing a new engine and fuel tank, and 1 fill of diesel in a local marina, my filters after several weeks looked like that. It took me a lot of heart ache to get rid of it once and for all. Also note that each diesel bug treatment is unique. I mean that the bug can be different in different areas, so make sure the treatment you get, is one that is useful to the bug that you have and in your area. One treatment that might be excellent for a person in another area, may be no good to you. Try to find out where you got the contamination. Most often its from a marina, or somehow water getting into your fuel tank thru a dodgy screw cap seal. Check your seal is ok, and if so, ask yourself if where you get your fuel is possibly the cause by asking other people if they have had a similar problem.
Every time i fill up, i add treatment as a precaution, and since I have done this, I have never had a problem.

 

[charles_reed]

Yes.

The only safe way to get rid of it is to drain the tank (you'll probably have to ditch the contents, because it's almost impossible to filter) and have the tank steam-cleaned. To do that properly I took mine out (it's usually difficult/impossible to dry them in situ)

My experience of using biocides on an infection is that they just exacerbate the problem.

Don't hang around, it'll just get worse and the diesel could set in a napalm-like jelly, if it's warm.

 

[Refueler]

Well looks like it. If it's jelly like then yes, if its hard and gritty no.

There are good replies here on the thread but also I have to correct a couple of things :

a) Bugs are not area dependent or significantly different according to location. You can have moisture based or Sulphur based anywhere in world and at same time.
b) Fuel can be recycled with only a little bit of work. It is not necessary to waste it if large quantity. Small - yes ditch it ! If you ditch it - then use a chatty container and ditch that as well.

We have to get you to a clean situation. So if you can bear to be without your boat for a couple of days ... here we go. (The below is based on a boat that steam-cleaning is impractical).

a) Siphon out your fuel tank as best as possible - Pela machines are excellent for this with a DIY knock-up of ally tube taped over the flexi pipe to keep it straight and controllable. If it blocks - then make up a larger bore pipe to siphon - I used the blanking cap for this, drilled and garden hose fitting ...
b) Get some diesel and a bug treatment bottle. Give a nice strong dose to the can and make sure well mixed.
c) If you have a garden sprayer with adjustable nozzle - excellent ... now fill that and spray the tank around inside with the b) mix. Try to get as much surface covered as possible.
d) Siphon out again and into same container as the fuel went (this will now start to kill bugs in it ...)

So we have a siphoned tank, a container of contaminated fuel with bug killer / diesel mix added. Probably you have a reasonable amount of killer + diesel mix as well left over. To this you can add a good measure of kerosine or gasoline to produce a solvent laced fuel. Now spray again with this mix... but take care to only spray for a short time as Kerosine / Gasoline is susceptible to static build up.... relying on the Diesel anti-static additives to dissipate it.
Let it settle in tank. If you can try to stir up the bottom. I actually use the large bore Pela tube I made to suck up the now breaking away crud ...
Once tank is empty again ... you can let this later fuel mix settle - but it's likely best to discard.

Now siphoning of the top of original fuel - by now should be reasonably clear ... plus it will have bug killer still in it ... you can add some of this back to tank. What we want to do now is draw this along pipework to the filter holder ... in so doing running bug killer through system. Siphon all through.

So stand all original fuel away in corner to stay quiet and settle out with killer mixed in. This will be best left for some days.

As best as possible check tank ... pour in some clean diesel .. siphon out and compare. It may be that you have to flush a few times the bottom till it's reasonable. The fuel used can be added to original fuel to stand and not be wasted.
Once you have a reasonable situation. You then take your fuel filter and add a strong dose of bug killer / diesel to the filter and bolt back in place. Fill tank partly with clean diesel and bug killer, pump through to prime system and start engine. (This filter filling is Volvo Trucks reccomendation ... and appears to work). Initial running will be uneven and appear to be bad - this is the bug killer not being a good fuel !! But once it clears the running will return to normal.

I would suggest that you change filter more often than usual for first season - depending on hours use - but possibly 2x in that first season. Checking it's visible condition. Hopefully it should be reasonable when taken out. Use a dose of bug killer at intervals - it is not necessary every fill up as you would have dilute killer there already from previous. The dose rates quoted for normal fills are safe over-dose rates and can be reduced significantly.
The original fuel can be carefully siphoned of and filtered - making sure bottom is not disturbed - and added along with fresh stock to use it up over time.

IMHO - some would suggest add Injector Cleaner - this I advise should only be done if tank and system is reasonably clean. They are based on strong solvents and can lift some pretty hard crud out of tank bottoms - clogging up not only filters but also expensively injection pumps !! Used from new and clean start - fine. But added to an old system - you may just end up like I did ... 10nm outside home port after long trip with a dead engine !!


Note : The above advise is based on my own engine / tank combo, (Perkins 4-107, standard filter assembly and a mild steel rectangle tank with baffle plate fixed under stbd fwd bunk), and what measures I took to combat a bug and sediment problem. 2 years later I am still in a clean situation with no re-occurence. I do not g'tee the above is successful for any other person - so please don't kill me if it doesn't work for you !! /forums/images/graemlins/wink.gif

 

[mbay]

What a brilliant and informative reply, but you've got me worried now!

I had the bug 3 seasons ago now and all i done was to treat it (won't say with which product thats a whole new can of worms) but it does appear to have gone, infact I only just changed my fuel filters a couple of weeks ago, they had been in since winter 08 and IMHO did not really need changing.

I would have liked to take the tank out and clean it but it would have been a really big job, so i took the bodge it route /forums/images/graemlins/blush.gif

 

[benlui]

Mbay, its likely your bug has long gone as you would have known by now if it wasnt.
As for taking out the tank, i think sometimes this is not a have to.
I took 6 solid ltrs of bug from my tank with a "pump drainer" and dosed with treatment. I changed my filters,and waited filled the tank again after treatment. Then added more treatment. This cured my problem. My local marine engineer couldnt beleive the amount of bug that my 65ltr tank had in it.
But, make sure you try this before going to the trouble o removing the tank. If i were to buy a new boat,or i was fitting a new fuel tank, i would have an opening/access hatch to same. This hatch could be very very useful as it would allow you to clean by hand and see into it.

 

[Bilgediver]

My experience of using biocides on an infection is that they just exacerbate the problem.

**************************************************

This unfortunately is your experience and not the norm!!!

If this was the case there would be no oil production from the north sea where the undersea control fluids are treated this way and numerous commercial ships would be stranded in the middle of the oceans. with seized engines or damaged fuel pumps.

There may be Snake Oil on sale from some sources however many of the products quoted here certainly do work as it says on the bottle however One has to revue the situation and use some common sense.

The procedure outlined by Refueler is certainly a fix all route and would work well where steam cleaning is not used however if one had a large attack of bugs such as one other poster then just dumping vast quantities of biocide into the tank is a complete waste of time as you will then have a big problem of dead bodies!!!! Not only will this cause you to spend the rest of the season changing filters at the most inappropriate moments, Usually in heavy weather, but the acidic contents will be doing nothing for the polished surfaces of your injection equipment or the interior of the tank.

Yes biocides do work but they really are preventative and not a cure and eradication for a major pandemic attack.

The bugs live in the water oil interface at the bottom of the tank. The bad design of the latest nanny state fuel tanks ensures there is a nice warm layer of water at the bottom of the tanks to provide incubation. Try and remove the water at the bottom of the tank and the problem should occur less frequently. Maybe fitting a drain is a possibility.

This water either enters during normal breathing of the tank or with contaminated fuel.

 

[John100156]

Refueler:

Great advics - I have a 550L tank which appears to be clean with no fuel bug at present - is it worth treating the tank at regular intervals as a preventative measure?

If so, what treatment would you recommend (name please) and at what intervals, in say tank fills (every time, every other fill, etc).

Many thanks

John

 

[Bilgediver]

Great advics - I have a 550L tank which appears to be clean with no fuel bug at present - is it worth treating the tank at regular intervals as a preventative measure?

***************************************************

The best preventative measure is to ensure you remove ALL the water from the bottom of the tank on a regular basis...Also remember that the wee beasties can build up imunities to biocides so dont become a creature of habit or they will return to bite you and block your filters. From time to time switch to other products.

There was a review of these products recently so maybe someone will come along with the names of the better ones however I believe it was a Starbrite product which did well in one or two reviews. They do two products which may confuse. One is Diesel addittive which amongst other things is said to disperse water which could be a good thing and help prevent bugs and they also do a Biocide which does what it says in the name.

 

[cliffordpope]

Why is diesel bug apparently only a problem for marine engines? With the popularity of diesels in cars, let alone lorries, you would have thought motoring problem forums would have been talking about nothing else. yet I have never read a single mention of the problem in cars.

 

[Heckler]

Cos cars dont work in an enviroment where water is always likely to enter the tank, cos cars use lots of fresh fuel so the tank isnt left to fester.
Stu

 

[Refueler]

[ QUOTE ]
Refueler:

Great advics - I have a 550L tank which appears to be clean with no fuel bug at present - is it worth treating the tank at regular intervals as a preventative measure?

If so, what treatment would you recommend (name please) and at what intervals, in say tank fills (every time, every other fill, etc).

Many thanks

John

[/ QUOTE ]

Honest - I cannot advise you on which one as we don't use retail types in the industry - the industrial versions are strictly controlled and not available outside.

When and how ? That I also cannot advise as it depends on how low you let tank go before topping up and how often you top up.
If you are a frequent fuel filler and generally only use half or less of a tank - then you will have bug dose still in remaining fuel when new added. The amount of killer needed in good low bug fuel is actually very low.
If you are in habit of running near empty or to low levels before refilling - then you would need to add more frequently ...

Honest answer ? Be sensible, no need to overdo it .. If it was me - and with this no g'tee for others .... I would possibly give a low token dose every 4th or 5th fill up if generally reasonable amount still in tank ... if tank significantly lower before refill ? maybe each 2nd or 3rd top-up ?

Really I cannot answer as I don't know your fuel habits.

 

[rich]

And don't forget the warm fuel that is returned to the tank,great for condensation when it cools down at night.

 

[wotayottie]

one tip for cleaning out the tank. I used gunk and a garden sprayer to get at all the sides and bottom of the tank. I then used a pressure washer to remove the gunk and dissolved sludge. the gunk smells much like garden plant killers (Jayes fluid for example) and certainly removed the slime very effectively.

water was removed from the tank with a pela type suction pump and the steel tank dried out with an electric heater - I used a heat gun.

diesel was treated with bug killer and then filtered several times though the wifes tights. all but the bottom one inch was returned to the boat tank and no problems thereafter until I sold the boat 3 years later.

 

[Mings74]

Thanks all, what a response!. I've just bought some Marine 16 which seems to get a good PBO write up. Depending on how that goes will move on to some/all of your suggestions. Cheers Ming