I have taken my scott water dome apart and found old copper crush washers fitted with tons of sealer.
Scottparts sell a viton o-ring for the spark plug ferrules, do i need to use any sealant along with the o-ring or not?
The aluminium water dome seems corroded since the previous owner seemed to of used straight water for coolant.
(1929 scott flying squirrel 500cc)
The corrosion is caused by different metals in near contact with each other Galvanic Action it is called, about the worst combination you can get is steel copper & aluminium. = area around the sparking plug ferrules.
see Technicalities 2.4.30 or Yowl Vol 9/12 (July 1976)