Quicksilver SAE 90 w. Remove the top vent first to insure it's not stuck, then reinsert it to keep from making a mess when you remove the lower screw. Take note that there is a fiber gasket either on the screw or stuck to the lower unit. Remove the bottom screw, again check for the gasket. Put a pan under it and then remove the upper screw again. Do yourself a favor and buy a pump and new fiber washers.
You should be looking to insure that the old oil is not gray from water infiltration and that you don't have metal shavings. A quart off oil will get you 2 oil changes.
