Shaft seal oil leak

[Jes Brinch]

Dear Forum,
I need your help. My dad and I bought our first boat a year ago, and wanted to service the engine ourselves.
I took the drive of the motor, but the oil started leaking from the shaft connection.
The motor is a Mercury F100PT, 1,7 liters from 2012.

Please take a look at my pictures. Could it be the radial sealing ring, not keeping the oil in at the crankshaft ?

Your help is much appriciated.

Br Jes

 

[merc850]

In pic.Nr3 oil seems to be running down the shaft so is this motor a 4cycle? If so, I tap out.