Mercruiser 2.5l 4 blade prop for watersports

s.hadley81

Petty Officer 1st Class
Joined
Jun 22, 2011
Messages
245
I have a couple 4blade questions? I have a 17ft bow rider with a 2.5l/120hp I use mainly for fishing but once in a while me and my buddy's have a getaway day where we ski/tube and grill on the island. I was wondering if I got a 4blade prop to get a better hole shot for playing would it be worth it ? I don't have a big problem getting on plane but with a couple people it could be better. Currently I run a 14" 19p 3blade and I run 4200 to 4500 wot depending on # of passengers and if the hull is clean (slipped all season) so my 19p 3blade is perfect. I wanna keep my wot rpm where it is so no one can Wind it too tight . So my questions are will my little 2.5l push a 4 and it do you think I would notice a big enough difference to justify buying a 4 blade to put on when we play? Also what pitch on the 4 blade would I want , I guess I wanna drop pitch. Sorry I didn't mention I run an aluminum now and would want a 4 blade aluminum because of where I boat. Any input is much appreciated!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,295
for watersports on the 2.5 and 3.0, generally you want to drop down in pitch for a better hole shot. adding a blade is like adding 1" of pitch.

I had 3 props in my little 17' Avanti with a 3.0. a 19p stainless, a 17p stainless and a 15p aluminum. the 19p was for cruising, the 17p for pulling tubers and the 15p for pulling skiers.

you are already at the low end of the RPM scale fully loaded. if you do decide to go with a 4-plade, I would suggest dropping down to a 15p
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
The Mercury Spitfire 4 blade is said to exchange pitch for pitch.Not required the reduce pitch to save rpm.
The 4 blade improves hole shot,maintains plane easier at reduced throttle,maintains its grip in rough water
and responds better around the dock.
 

s.hadley81

Petty Officer 1st Class
Joined
Jun 22, 2011
Messages
245
Ok I just wanted to post my results but I actually put a set of smart tabs on and they made a huge difference. I'm also gonna take Scott's advice and take one of my spare props (all 19p) that has a few nicks to the prop shop and tell them what I'm trying to achieve. They said they can change the pitch and maybe a slight cup to help me pull skiers, They always done great for me in the past ! Just figured I'd post to close out the thread. Thanks for the advice !
 
Top