I bought me a newer boat a few days ago after getting tired of messing with the old motor. This is a 1991 25H Evinrude. I was going to change the gear oil but I have a question about the directions in the owner's manual. First here is the picture it shows: If I understand this right, it says to fill it from hole #1 until it comes out hole #2. What is the reason for this, is it to make sure you don't over fill it some how or push the air out? I'm going to bypass the recommended lube that it states to use and use what Bubbakat recommends; Castrol Synthetic 80w-90.