Copper corrosion on fuel tube - what happened?

[tapkaJohnD]

I have an engine rig, that been sitting idle since last winter. I went to use it, and found this (pic) on the fuel pick-up tube. The tube is some copper microbore central heating tubing. It's not blocked inside, but further investigation found that the Facet Solid Sate fuel pump (behind the fuel tank tray) had failed. It pumped at first then only a dribble, and what came out had white 'bits' in it.

The old fuel was probably Shell V-plus. Has the small (?5%?) ethanol content attracted water, that has corroded the copper tube, assisted by galvanic corrosion with aluminium in the pump?? Or was it a chemical in the fuel? any ideas?

John

[GreenV8S]

Copper and aluminium have very different galvanic voltages. If they're electrically connected and also connected via an electrolyte, the aluminium will corrode rapidly. I expect the white debris is alu oxide. I don't know how the electrolyte formed. Neither petrol or ethanol are electrolytes, but perhaps you had water contamination in the tank.

[tapkaJohnD]

The only possible water in the tank would be from what was absorbed from the air by alcohol in fuel.
Tipping out what was in the tank, there was no gross water level, and as shown the corrosion on the copper is all over it.

Scarey, for classic car owners! In future, I shall drain any fuel after a test session

Would a "Fuel stabiliser" help? EG Wynn's Dry Fuel? https://www.wynns.eu/product/dry-fuel_consumer/

John

[Dogwatch]

By the look of it the pipe lay along the bottom of the can so would be right in whatever crud accumulated there over the winter.

Might help the pump if you could keep the pipe off the bottom of the can.

[Auntieroll]

Garden machinery dealers sell a fuel system additive which seems (in my experience anyway) to inhibit the formation of the type of crud seen by the OP. I have used it in cars, 2 stroke motorcycles/chainsaws, lawnmowers for winter lay up.

[TooMany2cvs]

tapkaJohnD said:

The only possible water in the tank would be from what was absorbed from the air by alcohol in fuel.

Scarey, for classic car owners! In future, I shall drain any fuel after a test session

UK unleaded has been E5 since the 1980s.