I'm about to change the gear oil in my Mercruiser 120hp sterndrive.

I've drained all the gear oil off with the drive in full tilt (so the drain plug is the lowest part of the sterndrive). Is it best to refill (into the drain / fill plug aperture with the vent screw removed) with the drive in full tilt position or with the drive fully trimmed down?

Thank you in anticipation of your advice.

Don't know anything about sterndrives but from a quick look at youtube,they seem to keep the drive unit down,you tube video,hope it helps. https://www.youtube.com/watch?v=rI57Mrny2MM

Thanks! I see in the comments section of that video they say to lower the drive.

Aye I could have picked a better video,I hadn't watched it all the way through and assumed he lowered the drive.

A good trick, to see if water is getting in there, is to let it sit overnight with the lower drain plug at its lowest position. The next morning (a day or so later is even better) remove the lower plug and see what comes out FIRST: If it's oil. you're all set; if it's water, then it's time for new seals. And don't be tricked if the oil that comes out is milky colored--aeration of the oil will color it that way.

Jeff

PS: When I do this, and no water (hopefully) comes out, I then try to push oil in from the bottom (with the top vent plug out). On mine, that does not have the aux oil tank, oil will come out right away IF the seals are holding.