I have been running XD-50 through my 2000 Johnson 225 HO but I am a little worried about the really cold weather this week. Couple years ago I tried to take off when it was 17 deg. and the oil alarm went off. I believe the oil "gelled" up. Not good. Anyone have a suggestion on an additive or something to keep it from doing this? If I have to switch oil's do I need to completely drain the oil reservoir or can you mix two different oils? Any help would be greatly appreciated thanks.