Thank you guys! Now that I have it out of the barn I can see that this would be the case. But I’m still not sure of which is the drain vs the vent for the lower unit. Neither of which are labeled like the “fill” and “vent” for the top unit.
There are two likely suspects here. (See photo)
Restored classic that I have had for a year. Runs good but a little crunchy engaging in gear. Tried to do my first gear oil change. I’ve done it in an outboard but never a I/O. Removed top breather plug, removed bottom drain plug. Surprised not much fluid came out. Maybe .75 qt. And it came out...
