I am in the process of purchasing a 1988 Bayliner Boat, with a 88 Mercury 150 HP outboard motor. The guy says the only thing wrong with the motor is that the seals on the right cylinder of the tilt & trim need replacing,(he has parts)..Is this a bad thing and is it expensive to have put on???? Any help please....Guy is asking what I think is a decent price for the boat, but am afraid may be more to this "seal" than what I am aware of...