Synthetic Oil

I have a 2.5 hp Mercury 4 stroke that is only about 6 months old. Recently I changed the oil, replacing the conventional oil that was in it with synthetic. Since then the drain plug is seeping oil around it. It’s a slow leak, but it’s driving me crazy. The plug is tight. Will switching back to conventional oil remedy this?
Thanks
SK

sounds like you need a new "O" ring on the plug

Agree that you need a "O" ring -- A dry "o" ring installed new will easily damage

O-ring or gasket

Quote:

---

Originally Posted by trypman1

O-ring or gasket

---

I agree. Its not the oil.

Synthetic oil will seep by seals and gaskets easier than conventional oil but, it can be stopped with good seals.

teflon tape if it does not use O rings