Yes, that is a carbon seal. You don’t need to split the case open to replace the O-ring inside the seal. While holding some downward tension on that spring, remove the C-clip around the base of the crankshaft. Under the C-clip is a small washer, followed by the spring, then a larger washer. Once the washers and springs are removed, carefully remove the black piece which is the carbon seal. Be careful with the carbon seal, as it can easily break. Inside the seal is an O-ring that needs to be replaced. Better yet, find a quad ring to replace the original O-ring. Assembly is the reverse of removal. Just be sure to hold downward tension on the spring so the various pieces don’t go flying all over the shop.
Edit – not sure on that model, but be sure to take special note of the orientation of the carbon seal when you remove it. Not exactly sure when the change was made but some models will have a raised lip on one side of the carbon seal – that raised lip side should face the crankcase. It almost looks like that black goo is the original sealer used to seal the case halves. At any rate, since you’ve already removed the powerhead, might as well replace the carbon seal O-ring.
Bob
1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
1982 Evinrude 25hp
“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."
