1996 Wellcraft V21 Suzuki 140 4 stroke clean cuddy Lots of Pictures

[THEFERMANATOR]

If you go larger diameter, you need to step down in pitch normally due to a larger prop hooking up better. Larger diameter props have MANY advantages IMO, but top speed is not one of them. Me personnally, I was always willing to sacrifice 1-3 mph top end to get all the other advantages that a larger diameter prop provided. Chances are you need about a 15x18 if you stick with the larger diameter. And lugging an engine by over propping is one of tge #1 causes of powerhead failure. Many think over propping is good as it keeps the rpm's down, but in reality you're KILLING your powerhead and putting unneccesary stress on your lower unit.