Changed the gear oil on the lower unit the day on my 2006 15 hp merc. Today when i went to fix the trailer lights i noticed that it had leaked a couple drops of oil. upon closer inspection i noticed that i had tightened down the screw and the seal was not sealing correctly and being pushed out. Backed it out just a bit so the seal wasn't being damaged and i have not noticed a leak. Has anyone else experienced this before?