Sealing rings

Hi Yassine,

More information please - engine type (914 / 912 ULS / 912 UL)?

914

Ah! - sorry all my experience is with 912's - I did have one, way back, with an adjustable fuel pressure regulator. Most 912's, now regulate pressure, by using a fixed aperture jet in the fuel return line.

The copper sealing washers are delivered as soft copper (annealed) and they work harden after the first use. They are not crush washers, they are plain flat copper washers that conform to irregularities in the mating surface to create a seal.   Most folks replace them each use, which is what Rotax recommends.  

Of course replacing them is the best, but in a pinch you can reuse one if you anneal it and then clean up the faces with some 600 grit sand paper.  Annealing is simple, just heat the washer to a dull red and then let it cool naturally.  This puts it back in a softer state so it will conform and seal again.  See link below.  

https://motoiq.com/wrench-tips-6-re-using-copper-washers/

 Rotax uses copper sealing gaskets on fuel banjo fittings and some oil fittings.  On the regulator of the 914 they use them for all the fuel lines.  They are to be replaced if you remove the lines and then fit them back together.  This is the always the same with copper seal gaskets, replace them.  (the crush gasket on the bottom of the oil tank for example) 

Cheers