Went to change lower unit gearcase oil and found milky substance and smelled really funny. A friend of mine looked at it and smelled it and said it must be a synthetic oil but the evinrude dealer changed it lasr and I was not aware of him using synthetic. My ? is I can't afford to have the seals redone now. Had them done by the same dealer 2 years ago and low hours since then but anyway. Can I just change oil often and keep an eye on this or is it going to do some major damage.