Looking to purchase my first boat (other than small aluminum fishing/duck boats) and I do not know a whole lot about I/O's. The boat I am currently looking at is an 1989 Sea Ray 220 Overnighter with the 4.3 merccruiser and alpha one outdrive on it. the motor has 760 hours on it but appears to run smooth and looks clean. The price for boat and tandem trailer is also very reasonable. how many hours can you expect to get from this motor on average before a new motor or expensive overhaul is required? it has been used in salt and fresh water. some guys say 1000 hours others say 1500?