oil slim on leg

[bluematt1]

Can someone say if this is normal have a 200 merc 1995 if run in a tub only big enough to cover front of prop (Is quiter)with muffs on seem to get some black oily slim on leg more at back of leg away from prop near where there is a little silver valve looking piece after 5 mins of running had oil changed at beginning of season only been out 3 times .
Is it just oil coming from exhaust I pre mix oil inj is disconnected
Anyone advise please so can sleep easy

[Burty]

sounds normal to me dude its just the residue coming out of exhaust