TOPIC: Selecting a motor using a jackplate 15.5' bell boy

Hi I'm at the point to selecting a motor but I'm concerned with the weight of four strokes, I would like a 70hp mercury or a Yamaha but that's a bit expensive, maybe that's overkill?
How about a 2006 60 hp mercury I think they are about 240lb
Just wanted to ask around before I invest a much if $ thanks for your input.