I have just polished and rebuilt the 2 fuel taps for the r90s and was wondering where to place the fibre washer/s. It has a large internal filter on top of the petlock. I have assembled them temporarily with 2. That is one between the petlock and the filter and one between the filter and the tank . However there seems to be a bit too much thread showing . It is 3 years since I took them apart and at my age - well Any advice please.