should change it every fall to make sure it has no water in it. If there is water and you don't find it, you could have a junk lower unit next spring
But just barely
I didn't change engine or lower until oil last yr figuring I didn't use the boat all that much.
Just changed both and the oil was TERRIBLE and the lower unit was really bad and really low.
So don't listen to Oldfish like I did😱
G3POBigDawgg LIKED above post
should change it every fall to make sure it has no water in it. If there is water and you don't find it, you could have a junk lower unit next spring
BigDawgg LIKED above post
Something I have to do soon myself. The lower unit seems to always have a little water mixed in with the oil.
PROUD MEMBER OF TEAM GEEZER ---------
Ascend 133X 13' - MotorGuide Xi3 & Mercury 4
replace the seals on the drain and fill plug also