Diesel Bug - is alive and well

iangrant

iangrant

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primary filter gunged up within about 4 hours of running and of course the engine slowed to a stop. Changed the filter and she ran fine again, checked the filter after an hours running and there again, black slime in the top.

So dosed the port tank with some 32 quids worth of some chemical that is said to eat the bugs and dilute the sludge, can't remember the name of it but hoping it works.

getting pretty quick at changing the primary filters now!


Ian
 
You can easily knock up a bit of kit to give you diesel a bit of a "scrub" Ian. 2nd hand in line pump from the local scrapyard and a cheap filter. Hook it up to the diesel feed before it gets to any of your filters and pump it round and round and round. Change the filter when it gets clogged and keep pumping it around until the filter no longer clogs up.

Not all black slime in diesel is the bug. Sometimes its', just......... black slime.
 
iangrant said:
primary filter gunged up within about 4 hours of running and of course the engine slowed to a stop. Changed the filter and she ran fine again, checked the filter after an hours running and there again, black slime in the top.

So dosed the port tank with some 32 quids worth of some chemical that is said to eat the bugs and dilute the sludge, can't remember the name of it but hoping it works.

getting pretty quick at changing the primary filters now!


Ian
Click to expand...

I checked fuel from the bottom of my tanks a few weeks ago and found loads of black bits and water in them. I was very worried about this (single engine) so decided to fit a polishing system to remove **** from my tanks.

It works very well and has cleaned up the fuel in my tanks so I no longer worry about it. It runs when ever I am running the engines but I do have the ability to run it when in the marina. It will allow me to polish one tank transfer fuel to another tank or polish both at the same time. Cost about £150.00 for bits, in the long run probably the cheapest safety device I have on board.

100_0812.jpg


If you want any further info PM me.

Tom
 
Thanks

Paul, Tom thanks for that, tried your idea this aft with a drill driven pump sort of working but the battery drill don't have enough grunt to spin the pump fast enough.

Tom PM inbound thanks

Ian
 
I have the same problem, although Princess have taken responsibility to get it sorted. Used the chemical and now on 3rd set of filters and I just wait to see if the tanks need cleaning.

Volvo do a bit of kit that goes in line before the pre filters and works on magnets or the like and I am told that for circa £200 it solves the problem for good. Anyone tried it yet?
 
I too have had 2 incidents of diesel bug on 2 different boats. Having used a biocide to kill the little beasties, I rigged up a cheap 240 volt drill pump which has a diesel proof impellor, for about 10 squids at Machine mart. I ran the inlet pipe from the tank side of the primary filter to the pump, and the return back to the tank filler, via a funnel with a fine gauze filter in the top. Circulating the 120 litres of diesel resulted in quite of lot of black slimy strands , resulting in the filter having to be cleared on several occasions. This method at least means you can see exactly what is going on. Having apparently inished, we polish the diesel by putting an old pair of SWMBO's tights into the funnel, and this took out furthr small particals.

I now routinely add biocide, and have no problems with pimary filter.

In the first case the engine stopped mid pasage, and we could get no diesel from the tank at all. Blew the tank back with a car foot pump which registered 18 psi before the blockage blew back - hence the remedy above. The RNLI by the way have two primary filters in parallel which are switchable on the fly
 
LS, and others.

Is there any chance of a diagram please, to show how you arrange the pipework and filters and pump for the scrubbing process ?



TIA
 
Tom's system is a bit posher and more permanent to the way i did mine. First trip out with my current boat the primary filter clogged and we limped back to the marina. I removed the primary filter and it was thoroughly clogged with black slime. Not sure if was the dreaed bug, or just a build up of crud in the tank. I have an in line 12v fuel pump from an old Astra GTE (same as any old 90's Vauxhall, bolted under the boot floor) that i have used over the years for various fuel transfer jobs.. It's 12v, high pressure and high volume. The inlet connection is about 1/2" or so and needs reducing for most installations. Easily obtainable from most car breakers for next to nothing. Plenty of new ones around too, like this one http://cgi.ebay.co.uk/Vauxhall-CAVA...arts_Vehicles_CarParts_SM&hash=item562b45be63

First thing i did was to buy a few primary filters. What i then did was to connect the pump to the fuel line just AFTER the primary filter and pump all the fuel out into cans, there was only about 20 gallons in the tank. I then tipped the fuel back into the tank, changed the filter and pumped it all out again. When i checked this filter, there was hardly any slime in it. I put the diesel back in again and left the filter in place. I changed the filter after a few months and there was more or less the same amount of slime in it.

Thinking about it afterwards, i realise i would have done just as well to have put the outlet from the pump back into the tank filler and just ran it for an hour or two until the filter didn't pick any more crud up. A few quid could also be saved by fitting the pump before the primary filter and using a cheaper filter, fitted into the suction side of the pump circuit.

Note the pump is high pressure, so the outlet must not be restricted in any way. Also note that these pumps were built to run all the time the engine was running, so no problem running them for hours on end. Mine is 15 years old and runs as good as new.

If you wanted to install a permanent system, but a more basic one than Toms, it would be pretty easy to fit the pump permanently, drawing the fuel in through one of the CAV type filters in Toms pic and pumping it straight back to the tank. This could be connected to a switch and run at will, connected to a timer to run for an hour every time you use the boat, or connected to the ignition to run all the time the engine is running.
 
Thinking it through

When the engine stopped the first time - it just lost revs then eventually stopped - I took the advice of the engineer and assumed it was the lift pump, fitted a new one and all was well until I opened up the engine, same thing again!

This time I changed the primary - blocked pretty solid, and when I tried to bleed the system it took ages to "suck" the fuel with the pump primer, when the side tanks are higher than the primary filters they normally fill themselves, I thought that was odd but eventually fuel came through. Theory number one:- having read through the posts and thinking it through:- sludge in pipe!

Back at the mooring I removed the filter and again full of black snot, fitted a new one and am trying the patent MBO suggestion of pipes and drill pump to draw the sludge through the primary having dosed the tank with a bottle of grotomar 71 which I'm hoping at £32 will help to break down the sludge.

Back down today with pipes and pump to carry on the proceedure and stink of diesel again

Thanks chaps for all the help and advice, will report back later.

Ian
 
Oh and

I've just been up to the shed to take apart the old CAV "sediment filters" they are just a cone in the top with a bowl full of sludge brown sediment.

It's no wonder the filtered units I've replaced them with blocked so soon and the other two filters up line were black!

Ian
 
gjgm said:
what filter system did you use?
Click to expand...

I'm guessing that was meant for Tom, but i'll tell you what i use. Primary filter is one of these :

http://www.asap-supplies.com/marine...e-filters/racor-turbine-500fg-seethru-bowl10m

Filters are about £7. Secondary filter is fitted to the engine and is a pattern of the Toyota filter that the engine is based on.

A polishing system could be built a bit cheaper by using a spin in CAV style system. The housing costs around £40 and filters are four or five quid.
 
yea, seems the filter housing can be the expensive bit, but it depends on what flow rate you want - and what your pump will deliver.
Seems there are two topics.. cleaning your fuel when its full of muck (in which case high volume might be the order of the day), and a polishing system... but do you need to polish if you dont have the bug ;guess your normal filters do that in effect ;)
 
gjgm said:
<snip> but do you need to polish if you dont have the bug ;guess your normal filters do that in effect ;)
Click to expand...

Good question. I don't think i had the bug, i think i just had some accumulated gunge. I also suspect that many of the cases of reported "bug" we read about are the same, just a build up of muck in the tank.

I gave mine a polish 18 months ago, last changed the filters a year ago and haven't had a problem since.

Giving some more thought to the subject, in particular Ian, i think i'd mount a 2nd hand Vauxhall pump and a CAV housing (scrap yard again) to a piece of ply, along with a few feet of pipe and wire. I'd give the system a thorough polish now and change the primary filters again. Then i'd monitor it and see how it goes.

The Vauxhall pump is very powerful and delivers a very good flow rate.
 
Last edited:
LittleShip said:
I checked fuel from the bottom of my tanks a few weeks ago and found loads of black bits and water in them. I was very worried about this (single engine) so decided to fit a polishing system to remove **** from my tanks.

It works very well and has cleaned up the fuel in my tanks so I no longer worry about it. It runs when ever I am running the engines but I do have the ability to run it when in the marina. It will allow me to polish one tank transfer fuel to another tank or polish both at the same time. Cost about £150.00 for bits, in the long run probably the cheapest safety device I have on board.

100_0812.jpg


If you want any further info PM me.

Tom
Click to expand...

Tom

Love the installation... would really like to do the same. Just one thing, & I hate to concern you, but you appear to have mounted the whole lot on some wooden planks... is that wise :rolleyes::D
 
Firefly625 said:
Tom

Love the installation... would really like to do the same. Just one thing, & I hate to concern you, but you appear to have mounted the whole lot on some wooden planks... is that wise :rolleyes::D
Click to expand...

I really wanted to fix it all to Fiberglass but try as I may I couldn't find a fiberglass tree :P

Tom

PS The racor500 is a great filter but in my opinion it is overkill for a polishing system. CAV will do the job just as well they filter down to about 5 micron which is all that is needed. The other point is you need to get the water out of the tank so you need the filters with the water trap on the bottom.
 
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