prop ?

[striperguy]

I recently perchased a 20ft crownline with a 5.0 volvo penta. My ? is what size prop would give me more top speed. There are no numbers on the prop i have on it now but it jumps right out the water, it runs about 33 mph at 4300 rpms does this seem right. Any input would be great thanks

 

[Brewman61]

Re: prop ?

The prop has the size on it. Would be helpful to know what size and pitch you're running now, and what the recommended WOT range is for your engine.

Running 3 or 4 blade? et.......

Generally speaking, more pitch allows higher top end, as long as you're not stressing the engine by running too much pitch.

Might be easier to find the numbers if you pull the prop.

For Example:

I have a Crownline 18.0 bowrider with the 220 hp MPI 4.3L.
I run around 4800 rpm, wot (If I recall correctly), and with a 14.25" X 21P 3 blade Aluminum, I get about 50 mph or so.
Switched to a 14" X 19P four blade Stainless prop- now get slightly less mph top end, but much better overall performance for my needs.

 

[striperguy]

Re: prop ?

Ok found the size 15x17, so i should try a 21 pitch maybe. thanks

 

[striperguy]

Re: prop ?

Ok found the size 15x17, so i should try a 21 pitch maybe. thanks

3 blade,sorry

 

[striperguy]

Re: prop ?

anybody else have any info on which prop. Thanks

 

[steelespike]

Re: prop ?

anybody else have any info on which prop. Thanks

Max rpm is 4,800 if your running 4300 wot with a 17 your rpm seems low to me.And if you go to a 19 or 21 you will lose even more rpm. I think there is a 220 and a 270 5.0 maybe others.Depends on the suffix.Does the boat respond when you trim up?Bottom clean ans smooth?