TOPIC: oil leak

I have an oil leak in my 1963 Johnson Super Sea Horse. I am new to boat motors, so can someone point me in the direction of what to do?

Does the motor run? From where the oil is showing up I would guess that the rubber "O" ring on the drive shaft coming out of the motor is worn out or missing. The blackish oil is more likely unburned fuel that is leaking through from the lower motor. I requires that the lower half be removed and replacing the seal, If you are going that far you might as well replace the water pump impeller and be done with it.
The ring in number 25 on this diagram.
www.marineengine.com/parts/johnson-evinrude-parts.php?year=1963&hp=75&model=75353C&manufacturer=Evinrude§ion=Gearcase

thanks, the motor does run