On my trim pumps it has a sticker that says 20w. I throw what ever cheap motor oil I have at that time in them. (I have leaking hoses that will be replaced this winter) 5w30, 10w30 15w-50 Mobil1. The only thing is I do not mix it with tranny fluid, that goes in my power steering pump (Dexron). and Always only Type-F in my Borg Warner trannies.

Now that I think of it I have a mini WalMart in my boat.