Sierra Cosworth Fuel Sender Repair

How I repaired the unobtainable Sierra Cosworth fuel sender part number 647686.
Initial problem was that it showed empty no matter what - due to standing for a long time with an empty tank the brass had oxidised which made is seize in the housing, then eventually I realised that it was made of brass and needed to be cleaned.

[@ElectromagneticVideos]

Interesting to see how those things are put together. I'm sure the sense current is small, but a bit surprising that the mechanism isn't sealed to prevent a stray spark (however small) for igniting fuel fumes.

[@eliotmansfield]

You need fuel, ignition and a spark for a fire - when it’s submerged there’s no oxygen and when exposed the air in the tank would be too rich for ignition is my understanding

[@ElectromagneticVideos]

@@eliotmansfield Good point and I get you need a limited range of fuel oxygen mixture for ignition - I'm just surprized they depend on that when for example a strong wind when your adding fuel might exchange the fuel vapor for air. Low probability of that happening but it did happen on an airplane - TWA800 - spark between some wires in the fuelk tank. Interestingly they have been retorfitting some planes with a system that keeps the empty space in fuel tanks filled with somthing like argon or nitrogen.