I am buying a new prop for my boat 2001 90hp 2 stroke Mercury.  Currently, I have the Mercury spitfire 12.5 x19 inch pitch.  I am wondering if going to the 17" pitch would be better.  I have read you would lose top end speed but hole shot would be better and I have also read just the opposite.  Any suggestions?

 

Lower the pitch the more torque, higher the pitch the more speed. Mercury has a prop selector tool that will give you the info you need! 

I went from a 17 to a 21 on my Merc 75.  I was turning too many rpms at WOT.  I had also installed a hydrofoil (SE Sport) which snaps the boat up on plane.  If I remember right my top speed is now 34-35 mph with a great holeshot in my 17.5' aluminum boat.  Quite a few variables come into play when selecting a prop.

First, you have to consider what rpm you are turning at WOT and normal load with the 19".  It you are at the manufactures max recommended, you might want to rethink that.  A 17" prop is going to have over reving the engine at WOT so you will not be able to run full throttle but yes, it would help your hole shot.

Now, if you are two or three hundred below recommended max, then going to a 17" would be a good idea, and if you really want to see a big improvement, get a Tempest and get rid of the aluminum junk.

Even if you are at max with the 19", going to a 19" SS prop will make a very noticeable difference.