Hi I have a '80 omc 140hp stringerr 400 and the current carb in the boat is a rochester 17059053. Problem is when using the carb selector on iBoats and other websites it shows that this carb is for a 90 hp omc. which carb do I need? I have looked and the best I could come up with was a Sierra 18-7608. I do not want to order the wrong one. Please Help. Thanks