Fuel filter - looks like a "jelly" substance

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bluemoongaffer

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I've had a few fuel problems all year (seems like an air leak) on my 1GM10 and as part of the work to try to fix it, I'm changing all the filters and hoses. I've just got the filter off that's on the engine itself. It looks / feels to have a slimy / jelly texture all around the outside of it. Is this normal (I guess not)? I'm going to change the filter anyway but wondered if there was a cause or reason for this?

Thanks
 
bluemoongaffer said:
I've had a few fuel problems all year (seems like an air leak) on my 1GM10 and as part of the work to try to fix it, I'm changing all the filters and hoses. I've just got the filter off that's on the engine itself. It looks / feels to have a slimy / jelly texture all around the outside of it. Is this normal (I guess not)? I'm going to change the filter anyway but wondered if there was a cause or reason for this? Thanks
Click to expand...

If it's black sludge, you've got fuel bug.
 
This jelly like substance has been mentioned a couple of times recently. Been found in the bottom of fuel tanks IIRC.

Something to do with using diesel with a FAME content ????
 
Sorry Bluemoongaffer there is no easy way to tell you this but ......You've got a BACTERIAL INFECTION.

There is no known cure except surgery which involves cleaning out your pipes and tank. If you are lucky it will not have spread further than the engine filter but in my case it went all the way to the injection pump.
 
You might want to try something like Marine 16 diesel bug treatment, in this list. The manufacturer suggests that a strong dosage will remove the slime etc and allow it through the filter to be burnt, Document here. Of course you will need to replace the slimed up filter.
 
If the OP has bio in his diesel and this jelly is a yellowish/translucent sort of deposit then I agree with Vic S ... I've had this and it wasnt the bug. It is caused by the biodiesel element of fuel getting past its shelf life and oxidising. Because of this, keeping your tank full helps by keeping both air and moisture at a minimum. Make no mistake, biodiesel lingering in boat fuel tanks for months on end is a disaster waiting to happen.
(this is as as well as the bio attracting moisture and thus encouraging bug ... a double whammy!)
Phil
 
You ask "cause or reason for this"

bluemoongaffer,There is a reason.This slime has to have water to live. My experence is of this was in curing 4 seperate fuel systems. Their tanks all developed a dark brown sludge that clogged filters. One common thing was water at the bottom of the tank. Once removed and fllushed and fresh diesel and refilled all went on to remain ok. But no more ingress of water.The important point is to modify the filler so that it is not directly on deck or out in the open. Either resite in a locker or fit a box around the filler with a drain over the side like the RNLI lifeboats have. chris.
 
Similar problem on 3gm30

Three seasons in a row in sept my secondary fuel filter has clogged solid with something resembling thick wall paper paste. Tank always treated with bug killer (starbrite biodiesel). I thought additive was meant to kill bug so that it would pass thru filters. My main filter is 30micron, the second one 2 (I think). Filters smell a bit fishy too. Tank is 100l filled 6 times a season. Any thoughts anyone?
 
When you fill up are you using proper offshore FAME free diesel?. If not, it could still be deposits of old polymerised bio content lurking around in your tank. It might have even been in your suppliers tank for ages. This stuff is not really 'bug' and wont necessarilly respond to treatment. Your 'wallpaper paste' analogy is just what I had, but mine was contaminating a can of road diesel I was using to do a top up. .... couldnt even pour it through the funnel's coarse filter! Phil
 
Never herd of road diesel being part bio' this is one for the chemists. I never have used anything other than traditional pink diesel. All I can repeat is that once the water,and it only takes a drop, is out of the tank it stays clean. I know it is some work but re route the standard deck filler,that usualy leaks, to a covered position. Alternativly, like I have done made an under deck box with filler at thy bottom and a lid and drain pipe to an over side hull outlet. Chris.
 
Thanks for all the feedback. I suspect that FAME diesel might well be the culprit here. I've used this all the time as it's a small tank and its been easy to fill by getting 5 litres from the local Esso / Shell. It then sits around in the boat tank for the season. I did have diesel bug a year ago but a thorough clean of the tank (so I don't think there's any water in there either) and a new filter plus an anti bug compound seems to have put a halt to that.
 
ACEA.

I have just read the following from Association of Civil Enforcements Agencies.
QUOTE
"Bio-diesel fuels are methyl esters derived from vegetable oils such as rapeseed, sunflower,
palm, soya or cooking oils. Collectively, these fuels are referred to as “Fatty Acid Methyl
Esters” or FAME. “Rapeseed Methyl Ester” or RME is the most common bio-diesel fuel
available in Europe.
Fatty acid methyl esters are produced by a chemical process that involves a reaction between
the vegetable oil and methanol in the presence of a catalyst, such as sodium or potassium
hydroxide. The by-products of this reaction are glycerine and water, both of which are
undesirable and need to be removed from the fuel along with traces of methanol.
The use of bio-diesel fuels cannot occur without adopting a series of precautions. Indeed,
unless the proper precautions are taken, biodiesel fuels can cause a variety of engine
performance problems including filter plugging, injector coking, piston ring sticking and
breaking, seal swelling and hardening/cracking and severe lubricant degradation. Bio-diesel
fuels also require special treatment at low temperatures to avoid an excessive rise in viscosity
and loss of fluidity.
Long-term storage problems can be observed as result of the poor oxidation stability of biodiesel
fuels. Thus additives may be needed to improve storage conditions. Furthermore, biodiesel
is an excellent medium for microbial growth. As water accelerates microbial growth and
is more prevalent in bio-diesel than in petroleum based fuels, special care must be taken to
remove water from fuel storage tanks to avoid operational problems such as sediment buildup,
premature filter plugging or storage tank corrosion."END QUOTE.

The last paragraph says it all, so no comment. Chris.
 
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