I have a 1971 sierra with a aq130c volvo-penta 4cylinder with a 270 out board. My prop is 14 3/8 d 17 p. I first bought the boat and took it out it only went 10 mph and 2800 rpm. I took it back and he had a mechanic look it over and he said it was to spec in all areas. I took it back out and it...
