Help with picking a prop 90hp on 18' fish/ski

[bobaschmidt]

I have a 1985 Ebbtide Dyna-Trak 176 S/S fiberglass fish & Ski with a 90hp Johnson. Currently I am running a SS 13 3/8 X 17 #389948. The boat runs good but the rpm at WOT is at 5800 RPM. OMC recomends 4500 to 5500 RPM. I want to keep the speed, currently at 41 mph (GPS) but if I increase the pitch what will happen to the low end and top end.<br /><br />I don't think it will pull a skier so the hole shot can be suffered, but I like the speed.<br /><br />I need a good recomendation for a new prop or is it possible to swap props.<br /><br />Thank you, Bob

 

[rjarreau]

Re: Help with picking a prop 90hp on 18' fish/ski

WELL YOU CAN GET THE PROP PITCHED TO A 19" IT WILLDROP YOUR RPM ABOUT 200 RPM'S AND GET THE PROP DRILLED AT THE LEADING EDGE OF THE BLADES TO INCREASE LOW END GOTO http://marinemechanic.com/site/index.html <br /><br />AND LOOK IN THIS SITE IT WILL SHOW YOU A GREAT DEAL ON HOW THIS DRILLING THE PROP WORKS AND ALL OTHER STUFF YOU EVER WANTED TO KNOW ABOUT MOTORS !!! GOOD LUCK

 

[Dhadley]

Re: Help with picking a prop 90hp on 18' fish/ski

Your top rpm is perfect if thats with an average load. If you are happy with the overall performance, dont change anything.<br /><br />If you are looking for more speed, you could try a 19" prop and raise your motor to gain back the rpms if you have sufficient water pressure now.<br /><br />Good luck!