2004 15HP Mercury 2stroke- Leaking oil?

[KiwiBoater2020]

Hey guys, first time poster here.

Ive just recently purchased a 2004 15hp motor.
I viewed the motor and saw it running in a tank of water and decided that i would complete the purchase as the motor seemed good to go.

Ive gotten home after a couple hours of driving to find a bit of oily crap leaking out of the exhaust below the water telltale
Ive also found it is leaking oil from the bottom if the prop. not a lot but some.

The guy assured me that it has been serviced, new impeller, leg oil, thermostat and all that but i am yet to check for myself as ive literally only just got it.

I got it home and chucked it into a tank of water and it runs like a "dream", starts first pull, idles nicely, a little bit smoky but im thinking thats maybe because it hasn't been used much in the past year and its a 2 stroke.

Ive attached pictures to show what im talking about

Any help would be appreciated.
Cheers, G

 

[Alumarine]

Looks normal to me.
Not all the oil is burned so the excess comes out the exhaust which is also in the prop hub.
It will smoke while running as well.
Sometimes synthetic oil will reduce both of those issues.
If you have to pre-mix then mix it 50:1. More oil than that will be more mess and not help the motor.