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Old 08-15-2023, 05:10 PM   #1
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Default Twin 4.3 with Bravo 3 dual props on a 2900

We have a 2005 2900 with dual 4.3 and Bravo 3 outdrives. Running 24P stainless props. she is slow getting out of the water but runs 50+ at 3000 RPM WOT. I usually run at 2200 RPM around 45 MPH. thinking of dropping the pitch just a bit to help with getting on a plane, any thoughts? anyone else running this setup?

Extended swim deck, lots of extra batteries and stereo equipment and full water and fuel tank add to our weight.
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Old 08-15-2023, 07:28 PM   #2
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45 mph at only 2200 rpm? All the boats I’ve seen wouldn’t be on plane at this rpm. Also WOT for these engines is around 4200 rpm so it sounds like you are way over proped which will shorten engine life.
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Old 08-15-2023, 10:28 PM   #3
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Looking for prop recommendations
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Old 08-15-2023, 10:35 PM   #4
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Quote:
Originally Posted by dogandpony View Post
Looking for prop recommendations
Have you tried the Quicksilver prop calculator tool? Google it.
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Old 08-17-2023, 04:05 PM   #5
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What are the Max RPM's at Wide Open Throttle (WOT). Max RPM for those engines should be 4400 - 4800. Anything under 4400 at WOT is more then likely either over weight or under propped (Assuming the hull is clean).

Over-propping will decrease RPM for the same relative speed, which is why it is perceived as being fuel efficient. It sacrifices time to plane and puts tremendous loads on the engine. I see a large number of folks with express cruisers trying to get to 24P for 'fuel economy'.

I've never seen anyone running a 24P prop that isn't over-propped.
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Old 08-17-2023, 04:12 PM   #6
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Also a weird combo. A 4.3 with a Bravo III? Seems like overkill. The Alpha 1 has a Max HP rating of 300 HP, while the 4.3 only puts out 190H. The Bravo III supports gas up to 525 HP.

BIII = 148 lbs
Alpha 1 = 85lbs.

That doesn't seem like much, but that is a lot of extra weight hanging after of stern on that boat.
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Old 08-17-2023, 09:52 PM   #7
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Over propped without a doubt! I would think 21 at the most if you are looking to stay a bit on the higher speed side.
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