Re: Mercury/Mariner leg oil
stocky<br />The "lower unit" oil drains from the big screw with a slot on the lower side of the gearcase, the rounded part in front of the prop. The "vent" screw is the same type of screw on the upper part of the gearcase housing, below where the gearcase housing is bolted to the mid-section. Pull both plugs , have the engine hanging straight down and drain. Fill from the bottom screw 'til it runs out the top screw, make sure both screws have their washers/gaskets on each screw. Gearcase holds about 22 oz. I recall. Buy a quart oil pump from your dealer and a quart of Merc lower unit oil and use the pump, a lot easier.<br />Backfire
