Anyone recognise this diesel residue?

[Erin]

I'm in the process of working through some improvements on the family motorboat and today tackled the fuel system.

The fuel filter/separator (Separ) has been gradually filling up with black sediment. I've tracked this back to the dip-pipe in the main tank which is encrusted both internally and externally with a soft black residue. I really don't think this is bug as the rest of the tank is pretty clean considering its age and we regularly use Soltron or Grotomar. It seems to be a reaction with the copper pipe which over the years has eaten into the copper. Does anyone know what it is?

And before you ask, the plastic spoon you see in one of the photos was what I used to decant all 290 litres . I've no idea where the marble came from!

[wiLlfish]

Originally Posted by Erin

I've no idea where the marble came from!

I noe wher itt cum fromm.

Itts de marbul owt ov a jiggul sifon.

Yew noe. Dem fings dat yew av too gett de rite rist akshun gowin.

S4r wud luv wan.

[Erin]

Originally Posted by wiLlfish

S4r wud luv wan.

I'll paint it orange and send it over to him.

[willk]

Originally Posted by Erin

I've no idea where the marble came from!

I used to joke about the lads putting ball bearings in my tank - I wonder....

[uncle al]

we used to call it s%$t in the tank well someone had to say it.

[Erin]

Thanks guys. Most resourceful and helpful as ever

[martini]

Originally Posted by Erin

Thanks guys. Most resourceful and helpful as ever

And you expected what exactly??

[colcreate]

Diesel reacts with Copper, Zinc, Brass etc. It's a complex chemical thing...... if water is also present (condensation) then = fungus and bacteria which generate organic acids which de-stabilises the fuel and increases the reaction.
Fuel lines should be stainless or similar.

[martini]

Originally Posted by colcreate

Fuel lines should be stainless or similar.

Bugger, that's another job for me then....

[Erin]

Originally Posted by martini

And you expected what exactly??

There we go, a helpful answer at last. Thanks colcreate.

Got a new pipe made up today out of steel. If it lasts as long as the old (copper) one I'll be quite happy.