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4.3 mercruiser - 23 pitch 4 blade prop

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Old 08-31-2017, 07:17 AM
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Default 4.3 mercruiser - 23 pitch 4 blade prop

Considering a 14 x 23 pitch prop (4 blade Aluminum Quicksilver Nemesis) for my 19 foot bowrider. The boat came with a 21 pitch 3 blade but the WOT easily goes beyond 4800 RPM. The 14 x 23 pitch I am considering seems to work perfectly: Max WOT at 4800 - Max speed at 50 MPH (best performance yet) - Best hole shot yet (225 lbs slalom waterskier). However, all the threads I have read suggest that a 4.3 merc should not be linked with a 23 pitch prop. Should I be concerned?
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Old 08-31-2017, 07:35 AM
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21 to 23 is roughly 10% WOT of 4800 will be reduced by 480 or so to 4320. That is too low. Lugging and overloading that small motor. What about a 22 prop? It wold top out about 4600. This is OSO. I gotta say it. Put a 350 in it...
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Old 08-31-2017, 09:36 AM
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many rec boat brands 17.5 to 19 ft with Merc 4,3 V6 engines come with 23 pitch 3 blade props. Sea ray, Glastron, Larson, Tahoe, and so on and so on
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Old 08-31-2017, 09:55 AM
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How far past the 4800 does it rev? Cuz the engine is happier as the load is decreased. If it'll only rev to 4000, the load is too high at all rpms. What about a 3 blade 23?
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Old 08-31-2017, 09:57 AM
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How far past the 4800 does it rev? Cuz the engine is happier as the load is decreased. If it'll only rev to 4400, the load is too high at all rpms. What about a 3 blade 23? Might be able to borrow one, instead of purchasing.
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Old 08-31-2017, 10:13 AM
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Default Boat performance with 23 pitch 4 blade

Tried my 2013 Campion 535i bowrider with a 14 x 23 pitch (4 blade) again today am am getting the following performances:
Got a max WOT at 4800 RPM
Max speed at 50 MPH...51 MPH
Best hole shot yet towing a 225 lbs slalom waterskier

These specs seem to tell me this is the best prop for my boat. I am VERY surprised since I had not heard of a 23 pitch 14 diameter prop on a 4.3 litre merc motor.

Last edited by OLDSKIER; 08-31-2017 at 10:26 AM. Reason: adding a blade spec (4 blade)
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Old 08-31-2017, 10:26 AM
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What is your drive ratio?
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Old 08-31-2017, 11:19 AM
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It is a 2013 535i Campion boat with a 4.3 merc. I suspect what comes standard for the lower unit with a 4.3 merc is the drive ratio ? Please tell me if it matters since the 23 pitch 4 blade works so well with the current set up. Thanks.
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Old 08-31-2017, 11:43 AM
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I believe it is a 1.62 or 1.68. If you are getting 4800 at WOT you aren't hurting the engine by lugging it. I was under the impression you were hitting 4800 with the 21 and wanted to run a 23.
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Old 08-31-2017, 12:02 PM
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Hello DERIKnKATHY,
With the 14 x 23 pitch (4 blade) I am getting a max WOT at 4800 RPM, a max speed of 50-52 MPH and best hole shot yet towing a 225 lbs slalom waterskier. I was never able to get these specs with the 21 pitch 3 blade. My only question is you mention lugging. Motor feels very powerful pulling me out, planes very fast also, even when pulling me out of the water on one ski. The max RPM is now at 4800... With the 21 pitch I could easily get 5200...which was above WOT RPM. I do not sense any lugging at any time with the 23. Hope I am writing the specs correctly as i do not want to be lugging the motor or having the wrong prop. Thanks again for the follow up. Quite possibly, the Campion 535i bowrider is a light boat.
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