I diasgree on the design defect "100%" statement.
Technically, although Yamaha would have plenty of legal legs to stand on if motors they sell die one day after warranty ends, FOR WHATEVER REASON, they would be out of business on the second day.
If it's not safety related, free market forces play, not the Fed government such as Coast Guard,etc, coming to your support.
No recreational user buys a motor with the understanding the motor will require $6K of work for no fault of your own, in such a short period of time, do they?
Based on the history of outboard motors which goes back way further than 2002 "Fs", never heard of such exhaust area failures, nor the balance shaft hardware premature failure wrecking the motor on F150s.
Pure and simple, Yamaha screwed up, and it's your money and property of value, you either take it laying down or standing up and fighting, that's only if the amount matters, otherwise it's just a different figure on the check you sign to the dealer's service department.
The internet is a wonderful place to educate and blog the living end out who cheats you, only if you believe you are cheated and if you knew when the dealer sold you the motors such an expense was possible at whatever failure rate now stated by dealers, would you have still bought the motors?
I'll never buy any F225, F250, nor F150 used unless all these parts being discussed have been replaced, period. Same goes for flywhell on the F350. Who only knows what's up with the new lighter replacement line V6s by Yamaha.