Changing oil in lower unit

[followme21]

I have a 84 Merc and am wanting to change the oil in the lower unit. Do I simply pull the plug on the bottom of the gear housing, drain and fill from the vent hole. Mine only has the vent hole on the left side of the top of the drive shaft housing. I have seen some that has a fill and a vent but mine just says vent, and only has the one hole. Do I fill in his hole? thanks in advance

 

[45Auto]

Re: Changing oil in lower unit

You fill it through the DRAIN hole. If you fill through the vent you will trap an air bubble in it and it will not really be full.

Most marine stores, Wal-Marts, or local hardware stores will have a pump kit (about $10) that attaches to the top of the oil bottle and screws into the drain hole. Then you work the little pump handle and it fills it from the bottom so no air is trapped in the drive.