I think Viton might be a better choice of material for O rings in contact with fuel
Originally Posted by C2RM
bmgermany take a look at this thread. Not sure what sort of filler cap you have. Mine is a 2006 4/4 and I bought the ring size as shown and it’s been fine

https://www.talkmorgan.com/ubbthreads.php/galleries/581614/3

I ended up buying a 2 pack of these - not expensive

BS232.NBR_PK2

BS232 3.53mm Section 69.44mm Bore NITRILE 70 Rubber O-Rings - Pack Size: Pack of 2 £4.14

I think a Viton O ring would be a better choice than nitrile, with it being in contact with fuel

Owen
"bilibib"
1982 4/4 Twin Cam, Royal Ivory
1932 Super Sports, Duo tone(two tone)Green