Need some help for prop!

[Jackie]

Hey guys,

spring is coming! so I gotta get my boat ready.I screwed up 2 of my props last year. So I have to replace it with a new one.
My boat is a 1992 Javelin 353B 15.25ft...it's got a 1992 70hp Johnson at the back. The prop that was on is a 13 1/4 x 17 pitch OMC prop. I was getting Max 5500 RPM and top speed 37mph...loaded with 2 persons and fishing gears
Now I just bought a 12 3/4 x 21 pitch prop...wondering what will happen with that? Will it increase top speed, slower hole shot, low RPM? or better hole shot, slower top speed, and higher RPM?? or neither? OR should I just stick with 13x17? or even 13x19?
Any input would be greatly appreciated!

Cheers,
Jackie

[ChampioNman]

Aluminum or SS? Only thing I would say is try it and see. You are definately going to bring the RPM's down with the 21.

[jaydee]

I think that 21 will bog your motor down and go slower. Too high a gear.
JD

[Jackie]

I see...I guess I have to stick with 17" then...
Thanks for the advise guys!