I've got a 90hp 2 stroke s/n OT087666 Merc. About 18 years old now. I check the lower unit oil frequently and for the first time I saw about a teaspoon of water come out with the oil. It was not mixed in and milky but was separate. I replaced all the oil and went on a boating trip putting on about 30 miles. I'll be checking more frequently for water now but I am wondering if it might be time to just go ahead and replace the lower unit seals. I haven't even looked in the manual yet so I thought I'd ask here as to how difficult that job is? Special tools required? I've done all the work that has ever been required on this motor, not very much but replaced water pumps, fuel pumps, cleaned carbs etc so I feel comfortable doing the work myself. However, if takes special tools to get the seals seated correctly etc. then I will have it done by an expert mech for motors from that era. Its been a great motor that I"m not looking to ever replace. I'ts got about 350hrs on it. 30% salt trips.
I do remember reading that to assure seals are working properly the lower unit should hold a slight amount of pressure.
I do remember reading that to assure seals are working properly the lower unit should hold a slight amount of pressure.