18 HP Prop Shaft Seal

[Too Cycler]

I am replacing the clutch dog in my 1972 Evinrude 18 HP model 18202R. Things are going fine BUT i am now confused. In ***embling the propeller shaft ***embly, the Seloc manual instructs me to install a new propeller seal at the back of the rear bearing head. The diagram in the manual shows a separate seal but my bearing head seems to have an internal seal the I cannot figure out how to replace it. The parts diagram for this model here on Marineengine.com shows no seal. I cannot imagine that there is no seal around the prop shaft. I took pictures but they are too big to upload here.

I don't want to put this all together and have it leak water. Any advice would be greatly appreciated.

[boats.net]

They don't list a replacement seal in parts catalog just whole head ***emble.