2003 Evinrude 250 HP Ficht. What is the purpose of the seal between the outside of the propeller hub and the gearcase housing ? I wrapped a lot of 80 Lb mono around the prop hub and when removing it a strip of fibrous material about 1/8" wide also came off. The parts breakdown seems to show the seal is pretty wide, should I worry about replacing it ? The prop is S.S. if that is a factor. I looked at a 225 Ficht, unknown year, and it didn't have a seal.