change gear oil mercruiser alpha one

[roffey]

I will be changing the gear oil in my out drive this weekend. There looks to be some sort of reservoir? From what I read on the net I think I have to remove both the fill screw and the vent screw, let the oil leak out. Put the bottom screw back in. I fill the reservoir until it leaks out the vent then replace that screw and keep filling the reservoir to the full mark?