I recently replaced my lower unit and am in the process of going through the break-in hours (I have 5 so far). Everything appears to be in fine working order, but I finally got the boat up on plane the other day and noticed a hard periodic "knock" or "clunking" coming from the stern. It seemed to coincide with the chop of the water like something was loose. I'm going to go ahead and drain the gear lube and inspect it, but short of that, any ideas on what might be causing it? I can't feel any change in the boat's power or steering - just kind of feel it through the deck. Would a bad trim hydraulic be possible? My trim is working fine, but sounds like it's laboring a little. I could just be paranoid of every little sound since I replaced the lower myself...
