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have 2000 260 br 7.4 310 hp b3

looking for prop info

seem little underpowered

cruises about 24-25 at 3200

anyone changed props from the originals?

will rev to about 4000 maybe if the winds right 40mph fresh water

thanks

steve
 
what props (pitch) do you currently have.

It sort of sounds like you are over propped....meaning 4000 RPM is a bit low for 7.4's
 
propes

not sure what ever came standard in 2000 on a 260BR 7.4L 310hp

will look next weekend when on boat

I believe it is two 3 blades which surprise's me as when I look for info seems 4 and 3 are the norm

thanks for the response will also look at the manual when I get home
 
So for your year boat, 3 blades were the only (well almost only) option...

It was not till 2010 ish, when Merc started offering 4 x 3 configuration.

But that configuration has NOTHING to do with your issues....meaning I have two sets of props, one is 3 x 3 and the other is 4 x 3.

I doubt the manual will tell you what you have, you might need to lift the drives into trailer mode to tell us what you have.

Bottom line, if you are sure your props are not messed up or have bottom growth or other issues, you should be turning 4600 RPM's at Wide Open, or something closer to that number for sure.
 
toofast,

what size and brand (i've seen both Merc XR and Hill Mfg.) 4x3's do you have ? What results did they give you ? I assume your 3x3's are 26' like mine.

(sorry for the hijack)
 
I have Merc XR 24 pitch 4 x 3
My 3 x 3's were 26 pitch

Biggest advantage is I can cruise SLOWER with the 4 x 3 without dragging as much. Which is only helpful in a choppy lake.

Depending on where you boat, you might see no difference.

If you want to chat, we can always review my detailed findings on a quick phone call, just PM me.
 
Hi Toofast
your right on, just got specs from Formula
stock props 3 x 3 22 pitch
WOT 4700 I am around 4000
@ 3000rpm I should be 27mpr
@3400 I am at 25 mpr

I know I have some light scum on the bottom ( Lake Winni NH )
and I do have a little vibration at low RPM
so a check of the props is next
maybe they have a small ding

will have them reconed during the winter

thanks for the input
 
Yep, find a good prop shop - might be your issue !

Best of luck and let us know what you find out.
 
Jed,

Do you have 375 HP 496's in your 31? As for your commentary above regarding 3 X 3 vs 4 X 3, just wondering if we "basically" have the same power package.

In another thread, I seem to remember you mentioning seeing about 30 mph at 3300 RPM's with your boat. I'm about 2 MPH behind that, which I would expect to be reasonable considering the wt. difference in a 31 and 34.

My wheels are tuned such that my max RPM's are right in the middle of the manufacturer's target range, and with that said, my speed numbers are right in line with what Boattest and Formula publish. I have heard others mention faster numbers on a 34 with 4 X 3 though, but that does not seem to play out on your 31.
 
V1rowT8 said:
Jed,

Do you have 375 HP 496's in your 31? As for your commentary above regarding 3 X 3 vs 4 X 3, just wondering if we "basically" have the same power package.

In another thread, I seem to remember you mentioning seeing about 30 mph at 3300 RPM's with your boat. I'm about 2 MPH behind that, which I would expect to be reasonable considering the wt. difference in a 31 and 34.

My wheels are tuned such that my max RPM's are right in the middle of the manufacturer's target range, and with that said, my speed numbers are right in line with what Boattest and Formula publish. I have heard others mention faster numbers on a 34 with 4 X 3 though, but that does not seem to play out on your 31.
Click to expand...

Yep same power package - other than yours had Volvo externals vs. Merc :)

Yep - 30 MPH around 3300 RPM - 1/2 tank guys, 3 people, flatish water....trimmed nicely.

As for FASTER NUMBERS - do you mean Cruise or Top End, either way NO WAY for me are the 4 x 3's faster - either way.

Top end is about the same, I get about high 40's (close to 50) on both props.

I can stay on PLANE at slower speeds on with the 4 x 3, and I cruise a BIT SLOWER....but by a bit I mean 2-3 MPH in the cruising range.

I am not sure the COST difference is worth it for anybody, unless you need new props, then 4 x 3's MIGHT make sense for you.

If I was on water that was flatter or rolling more than step chop, I would use my 3 x 3's all the time. Right now they are simply a hot spare.

Interesting read...

http://www.boattest.com/resources/view_News.aspx?NewsID=3276
 
toofast said:
Yep same power package - other than yours had Volvo externals vs. Merc :)

Yep - 30 MPH around 3300 RPM - 1/2 tank guys, 3 people, flatish water....trimmed nicely.
Click to expand...

I just noticed your engine/drive info at the bottom on your signature line. Should have looked closer before asking!

The 3 vs 4 thing applies in prop driven aircraft as well. 2 vs 3, 3 vs 4, ect... Same physics, different medium.

Thanks for the insight, and best regards...
 
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