Please help me choose a prop

[Cigarboater]

Hey everyone,
To make a long story short I have a 2000 Four Winns 248 Vista. Its heavy 5800 dry. It is powered by a Volvo Penta 5.7 GS 250hp and a Penta SX drive. I know its alot of boat for the motor. Anyway its currently got a Solas 4 blade aluminum 14.75X15 on it. I am hoping a better prop will get me better preformance. Currently the boat will plane decent with tabs and trim in and 2 people once it planes it will run 4800 RPM at WOT so thats pretty much right were id want it. Not sure the speed no GPS. With more than 2 people it will not plane unless we put most of the people in the front. Also once on plane it will fall off around 3800 RPM really it cruises best at 4100. Can a prop help me I have had so many recomedations I dont know where to start. Heres what I have been told so far. A Powertech ELE4 4 blade stainless 15X15. A Mercury Black Max 16x14. Also a Mirage Plus 15.75X15. Oh one more thing when it will not plane off it goes to 3800-4000 rpms and plows water with the nose in the air at about 5 mph. So is the prop not biting or not enought power to push it over the hump. I know its never gounna be a race boat I am just hoping to make it a little better. Sorry for makeing a long story long. Thanks.

 

[steelespike]

Re: Please help me choose a prop

I think you have issues other than a prop.250 hp should plane easily on a 15 and likely over rev.Without your speed can't tell how you are really doing.
You allready have a prop that should have good hole shot
stay on plane with reduced throttle,and your running at max rpm.
Typically when struggling to plane etc the solution is to drop down in pitch
And that probably will improve hole shot but you will be over reving at wot,
and likely lose some top end.If you look at the prop chart for a 5.7
you will find about 4 props lower than a 15 and about 13 above.
I think a healthy setup would run something like a 17 and still have better hole shot and top speed.
Some things to look for:: Bottom clean and smooth?
Throttle plates opening all the way?
Does it have careful tuneup with a compression check?'
Is it running on all cylinders?
Sometimes boats absorb water in the floatation in the hull usually puttng a bunch of extra weight in the stern where it does the most damage to hole shot etc.

 

[Cigarboater]

Re: Please help me choose a prop

Im not sure that this boat even has foam in the hull I was under the impression that was only in smaller boats. The stock prop on the boat was a 15.5X15 aluminum prop. As far as good compression not sure the motor runs very well. Well I guess it does except for this. The previous owner said the boat did 36 on GPS with the solas prop on it. Thats about what it feels like. Speedo says about 32 but I dont trust it thats tabs up and trim up.

 

[steelespike]

Re: Please help me choose a prop

When you say stock prop you mean listed in the owners manual or was on the boat?
It sure deoesn't seem it should struggle so. Doesn't seem likely that a boat company would build a24' boat that won't plane with more than 2 people aboard.
A compression check would give you the chance to note the location and condition of the plugs.Maybe the timing,be sure it is set right and advances as it should.