Water in diesel

[Bee]

Right. The boat is now getting on for 10 years old, it has a large integral fuel tank and has been tossed about some large and rough waterways, big European rivers etc with lots of wash with no probs. Every winter it gets a shot of fuel treatment and the filters are always clean with no black slime. Early this year I started the engine, it ran for a few minutes, clattered and stopped, bled it, same thing, fuel smelt like white spirit and would not start. I have a small inspection hatch just big enough to get an arm in and when I looked in with a torch the fuel was just a horrible orange mess with a bit of water underneath it. I put a bilge pump in it and pumped out about 150 litres of useless fuel into barrels. Two packs of nappies later it was better BUT some of the little absorbent gel things had escaped into the tank. It took 4 days to clean the tank and put in fresh fuel. The lesson is that an inspection hatch is a GOOD THING, a drain cock would have left a bucket full of crud in the tank. Also I suspect the fuel additive had just mixed the water into the fuel until it would no longer burn. I have now bought a little 'Rule' bilge pump that I will use every year to suck out the bottom layer of fuel and be more careful about fuel additives. I do not know how that much water got into it but if you are thinking of crossing rough water in your boat I would be v. careful about your fuel tank. Oh by the way, it was all white diesel in the tank, no red and no rust in the tank.

Edited July 29, 2016 by Bee

[Nightwatch]

I dose my tank with Marine16. Can I ask what additive you used to use?

 

Just an interest.

[Guest]

We had water contamination in the tank a few years back. No inspection hatch unfortunately, but I usually dip a long tube into the tank in spring, and often get a few drops of water out with a pump. Well worth the effort IMHO.

Our problem was brought about by a leaking seal on the filler cap. These cost 70p and a tank of diesel costs 70 quid +. I usually change the seal when taking on a full tank, and definitely before winter layup. I have been ridiculed on here for this, but hey ho! I also fasten a plastic sheet over the filler during winter layup. I hate the brass type fillers and would go back to a BSP stub with a female cover on another boat.

[Bee]

I dose my tank with Marine16. Can I ask what additive you used to use?

 

Just an interest.

To be honest I can't remember but whatever I use in the future I shall read the instructions more carefully.

[john6767]

I dose my tank with Marine16. Can I ask what additive you used to use?

Just an interest.

Marine 16 is a demulsifier, so it's mode of operation is to separate the water out, so you would expect water in the bottom of the tank that you need to regularly drain off.