Prop for 2000 Evinrude 75HP Ficht

[BoatKid23]

I currently have a 13.75 X 15 pitch prop on my 75hp evinrude. It is the factory aluminum. The boat is a 2001 Starcraft 16' Supersport. Currently the boat hits 41-42 mph GPS speed. If I upgraded to a stainless prop would I hit 50 mph? I originally had a 13.25 X 19 Aluminum when I got the boat and I was only able to hit 4200 RPM's at W.O.T. The W.O.T. range Evinrude recommends is 4750-5250. With the 15 pitch I have on now I get 5200 RPMS W.O.T. What size prop would you recommend. With 4 people in the boat I still hit 37 mph GPS speed, which I think is still pretty good.

 

[DJ]

Re: Prop for 2000 Evinrude 75HP Ficht

BoatKid,<br /><br />At 5200 rpms. you've nailed it.<br /><br />The only way you are going to hit 50 is with about 50 more hp.-Sorry. <br /><br />It takes a lot more hp. to increase speed even slightly once you get above 40.

 

[BoatKid23]

Re: Prop for 2000 Evinrude 75HP Ficht

Hey guys,<br /><br /> Just a quick question for you. I can buy a quicksilver stainless prop 13 1/8 X 16 pitch for $265 brand new. Would that prop peform better than my 13 3/4 X 15 and still allow me to achieve 5200 rpms? Am I going to notice any difference from my aluminum to a stainless?

 

[DJ]

Re: Prop for 2000 Evinrude 75HP Ficht

Boat Kid,<br /><br />I would not go to the 16" particularly if it is stainless. Sorry. <br /><br />Stainless props tend to bite better than aluminum, thus holding the rpm. down for a given pitch vs. aluminum.<br /><br />You may find that a 15" stainless may drop you down below 5200.

 

[Dhadley]

Re: Prop for 2000 Evinrude 75HP Ficht

They will bite better and you can run a higher X dimension. That should help get the RPM's back. It's more than just buying a prop and sticking it on.<br /><br />Good luck!

 

[BoatKid23]

Re: Prop for 2000 Evinrude 75HP Ficht

So what size would you recommend to keep the RPMS in the 5200 range? I thought that the 13 1/8 X 16 pitch should keep the rpms in the same range as the 13 3/4 x 15 pitch since the diameter on the 16 pitch prop is smaller. I understand that there is a sort of science to propping a boat, I hope I would be able to get some insight on the forum to help me out. Thanks

 

[Dhadley]

Re: Prop for 2000 Evinrude 75HP Ficht

When you say its a Quicksilver, do you mean its a Mercury prop? If so, does it have an OMC (Bombardier) style hub? Lets make sure it'll fit first.<br /><br />What we are saying is that the 16 being a larger pitch and SS it will bite harder or grab more water therefore be harder to turn 5200. At the same time because it bites harder you can run the motor higher on the transom (increased X dimension) to reduce drag. That will allow some RPM's to be gained back. The down side is the smaller diameter. That limits the X dimension. Personally I prefer a large diameter and extended cup. I also like progressive pitch and aggressive rake angle. <br /><br />Isn't that an aluminum boat? This is going to be interesting with 75 HP V4 and a 2:1 gear ratio. If you still have the 19 you might consider trying it again at a higher X dimension just to see what you gain.<br /><br />Keep us posted!

 

[BoatKid23]

Re: Prop for 2000 Evinrude 75HP Ficht

Thanks for responses. The boat is an aluminum 16'1". When you mean (x-dimesion) you are talking about raising the engine correct? Right now I cavitate or lose the grip on the water usually when I am trimmed up more than 1/2 -3/4 of the way depending on the conditions of the water. The quicksilver prop has an OMC hub on it..I found it on the overton's website. Thought $264 for it was a good deal, but I don't want to get the thing and not have the boat perform correctly. I do a lot of cruising in the upper RPM range and I do like to ski/tube occasionally. Right now I can pull a 200lb person out of the water easily so I don't want to loose that ability. If the quicksilver is not the way to go does anyone have any suggestions on what diameter/pitch/manufacturer prop would work well with this combination?

 

[DJ]

Re: Prop for 2000 Evinrude 75HP Ficht

BoatKid,<br /><br />A stainless (cupped) prop. will help you with the cavitation problem somewhat. Cupped props. tend to hold better.<br /><br />You are right on the edge of your max. rpm range. I think the best thing for you to do is find someone that will work with you on trying a prop. or two before you buy. You do not want to shell out $250.00 only to find out you went the wrong way.<br /><br />If I had to guess, I would try a Quicksilver 15". The QS props. are good ones.

 

[Solittle]

Re: Prop for 2000 Evinrude 75HP Ficht

Boatkid - I doubt that you will pick-up nearly a 25% increase in speed by changing props when the one you have is dialed in. I would keep that money in my pocket or put it in the gas tank and that should buy a bunch of gas even at todays prices.