TOPIC: Replacing lower gear oil...

When replacing lower gear oil, how much should come out?
And about how much should go back in?

I used a pump on the lower drain hole, until it came out the top drain hole, when it stopped oozing I put the plugs back in.

Also what should the old oil look like?
The stuff I drained out looked like coffee with a greenish tint.
Does this mean I have water getting in some where?

This is my first outboard, and the first time changing lower gear oil...

Thanks,
october

Hi,
If the outboard was not tilted when refilling, then the procedure used is correct.
If a little time has passed since the outboard was last operated, most often, most water (if) present will drain out first. If the outboard was recently operated, then most the lube will be milky with water (if water is present).
Discolored lube indicates a too longer service life (like not changing engine oil in a timely manner).
So many issues and cost could be saved if more marine drives were given a little maintenance as done here. Far too many suffer costly freeze and/or water damage.

Regards,
Joe
www.fergusonpoolemarine.com
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FP has it right. Personally, I replace the lower unit oil at the end of each season. There is some water that gets in mine (the milky color) and I don't want it to become a freeze issue over the winter.

I agree. Gear lube is cheap compared to a cracked housing. I change it every year at the end of the season also. It is the best way to check for a bad seal before it becomes a problem.
Bill

Ditto:

All Dunn II. I learned on a Merc MK55
Check and change lube each season.
I found a busted lower unit. Because I didn't change lower unit oil in the fall. Oil is cheaper that a lower unit!