That number is for the rubber washer that goes under the screws with the cup shaped screw heads on the later pressure tanks (1958-59). Is that what you are looking for? If memory is correct, I used to use o-rings instead. OR the 304137 screws that came wish the rubber sealant washer already on them Evinrude Johnson OMC 0304137 – Screw, NLA (marineengine.com). At today’s prices, the o-ring sounds a lot better.
