Did the mechanic ever say why the lower unit was causing the motor to lug?
he showed me. The gears were just chewed up and worn. SEI said it was due to not properly breaking it in. My mechanic said that wasn't true. But that's another argument. Replaced the lower unit and finally my boat would plane out again and run like it was supposed to.
Improper break in is a excuse for companies to void warranty. A lower unit does not have a "break it" basically launch the boat. Shift forward and reverse to make sure the shims are compressed and shifting correct length then go fish. The gears will naturally align and eat correctly if it's built right. There is no excuse for gears to eat without there being a cause (stump, bad build, ect). My opinion.
I agree. It isn't like a clutch, piston ring, or brake pads, where seating is going on. Basically, how the gears mesh on the very first revolution, is how they should stay for the life of the gear. The "life"'of the gear depends on the builder and quality of components.