Re: Outboard inspecting questions.
Yep. If you can't verify the actual maintenance history, drain and refill the LU. Should be done annually anyway. Yes, refill it from the bottom, or you will have a challenge getting the lube into the case. That also confirms that bubbles are out. The LU lube level is important. Not overfilled ever (causes insufficient expansion room), and not low (might starve and wreck the driveshaft bearing).
Look for water and/or metal fragments in the drained lube. If you find ANY, plan on replacing the appropriate seals and/or parts. If the motor ran recently, water will have blended into the lube, and make the lube milky. That's still water in the lube, and the problem should be corrected.
Ditto for the impeller -- if you go through all the labor to inspect it -- and you should, change it. If you have the LU apart for any reason, consider replacing the shift rod o-ring(s). Cheap, and often overlooked.
On motors that use nylon LU drain plug seals, they can sometimes be reused, but often a backyard mechanic has used an improper screwdriver to remove the plugs, or severely overtightened them and they're mangled. That means to install new drain plugs to save future headaches. Since the seals are cheap, and you have the plugs out to drain/refill, replace the drain plug seals at the same time.
