Early 90's 174 zw top speed/prop question

[mmead1014]

To start with I'm a new boater so I'm learning as I go. I just picked up a Cajun Adventure that was well cared for and has a 2002 115 Merc 2+2, with a 19 p aluminum prop. The motor was taken off a pontoon boat and was never repropped. On my first venture out with it the boat was loaded down with 3 adults and 2 children. It was in the morning and the water was very calm. After getting it on plane and trimmed I was topping out at GPS 40mph. Is that what I should be expecting? I posted this in the general boat forum and it was suggested that an SS prop would help a lot, and going to a 21 or 22 p would be a good idea. And someone mentioned something about the blades being cupped at the correct place for bow lift.

Any help or words of wisdom would be apreciated

[316jughead]

What was your wide open RPM's?

[mmead1014]

What was your wide open RPM's?

To be honest I don't know, I hit 5400 RPM and stopped. I don't know how much throttle there was but there was definettly more. I didn't want to screw anything up.

[316jughead]

It's very easy to over trim and throw out a big rooster tail behind the boat. This means that the prop is not holding water or biting and you will turn rpm's but not go anywhere. When propping keep the rooster tail to about 2 feet. I sold this boat with the Evinrude 115, and we used a 19 pitch SS. I imagine that your newer 115 is putting out more HP, if you could try a SS prop that would be great.