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Old 07-25-2012, 12:16 AM   #1
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Default Good Rpm Question Havn't Seen Asked!!

Hi all,
New Maxum owner here. We have a 2001 2300 Sr 5.7 250hp 19 3 blade aluminum pitch prop in great condition and it has everything we could ever ask for in a boat and super happy!! My question is when you talk WOT RPM range (2400-2800) is that RPM with the drive fully down or trimmed up a tad to achieve it? I do not have trim tabs (considering it though) and a dolphin tail (previous owner installed). I can get about 4200 RPM just under 36 MPH GPS with two onboard and about 3/4 tank fuel and usual gear with trim down. I can trim it up a little and get close to 39 MPH at 4700 RPM. Am I in the ballpark? Our usual load is a little less in the numbers with 2 adults, 3 kids under 16, full water and not too much gear. Not sure where to start with getting added performance after reading 49 MPH normal MPH if I don't know how to judge outdrive position tabs etc. Thanks and I hope any replies help not only me but others as well !!!!
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Old 07-25-2012, 01:28 AM   #2
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First welcome to the website! To answer your questions it is all in the pitch and wot. What does your manual say?

It sounds like you are getting close on all this. Trim is very important too. Your sweet spot is what your looking for.Your splash should be right behind you when you are driving.

Good question and have fun trying to achieve your speed and wot.

Roger
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Old 07-25-2012, 02:24 AM   #3
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Hi Jodie Lynn, the MAX WOT RPM for the 2001 5.7 is 4400-4800 RPM. You should never exceed 4800 at any time (trim up or down) and as long as you are in the range, you are pretty good. The fact that you are at 4700 means you could probably push up to a 21P and get a few more MPH out of it. You will probably loose about 200-300 RPM with the change though so you will now be on the low end with trim up. You will also sacrifice a bit on the holeshot (a bit more if loaded up too). I am not sure what kind of speed you should get on this but would have expected a bit more than 39. I have a 96 2100SR with the 5.7 2bbl (235hp) and can get about 52-53 at 4300-4400 (my range is 4200-4600) with the 3 blade 19p. Was getting 54-55 with a 3 blade 21p but only turning 4000-4100 with it.
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Old 07-25-2012, 04:29 AM   #4
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welcome to the zoo....can't add anything to these guys posts...they pretty much answered it....wot= wide open throttle which is after you trim the boat out with either half fuel....2 people and moderate gear....


SP
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Old 07-25-2012, 10:19 AM   #5
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Great thank you guys. Now I know and can be more in tune with her. Great website BTW!!
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Old 07-25-2012, 10:48 AM   #6
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I have the 2300SC. My max is around 42MPH@4500 with a 3/19P. I think the 19P is going to be the best prop for you. You can try a 21P but like others have said, you may see some drop in the holeshot. Especially if you start pulling the kids around on towables. Are you measuring speed with GPS?
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Old 07-25-2012, 11:24 PM   #7
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On my 95 2400 SCR am running a 3-19p run by a Merc. Horizon 350 EFI and am getting 5100 RPM and 46 mph at WOT.
Hardly ever run at that speed. Engine in run by ECM and cannot over rev. Thinking of going to 4 blade.
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Old 07-25-2012, 11:33 PM   #8
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Yes GPS but its an old one about 1997, not sure if that matters but I will try with another one. I just bore out the speed pitot hole in the outdrive and I now have a working speedo to help out!! How accurate are they though? We do the tube thing with the kids and I too think the 19 Pitch prop is right for us. Maybe next year I will look into getting electric trim tabs. The smart tabs seem great to everyone but the quality and lack of total control when we venture out in the Intercoastal waterway is steering me away.
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Old 07-26-2012, 02:27 PM   #9
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Speedo's are not that accurate. GPS is.
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Old 09-06-2012, 10:59 PM   #10
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Correction .....Just noticed the GPS was reading knots KNTS which turns out to be about 45 mph and speedo reads about 45 mph YEAH!!!!
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