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Do I have the right Prop - 280 EC

seguirseguir Member Posts: 170 ✭✭✭
in Rinker Express Cruisers Forum
Ok, I got the boat out of the water and checked the prop size....Bravo III 350 MAG 5.7 MPI.   The pitch is 20.   Seems low.   In past post I was complaining in order to keep the boat up on plane I would be pushing 3800 RPM's doing 20 to 22 mph.  I am unsure how this works but should I be considering a 22 or 24 pitch. or does this work the engine even more?
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    Black_DiamondBlack_Diamond Member Posts: 5,439 ✭✭✭✭✭
    You really need to know your WOT rpm as-is.  From there you can look at pitch changes and the effect on rpm.  Generally about a 200rpm change per inch of pitch.

    Past owner of a 2003 342FV
    PC BYC, Holland, MI
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    seguirseguir Member Posts: 170 ✭✭✭

    In my merc manual it states my WOT is 5200.  

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    Black_DiamondBlack_Diamond Member Posts: 5,439 ✭✭✭✭✭
    So the trick is your real WOT in the water, on plane, trimmed out. Then you compare and have a pretty good idea of any pitch change to make. The BIII moves in 2" increments, so a 22" from a 20"P will lower your rpm about 400 rpm and vice versa.

    Do you have trim tabs? They make a big difference.

    Past owner of a 2003 342FV
    PC BYC, Holland, MI
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    seguirseguir Member Posts: 170 ✭✭✭

    Thanks guys....Year one with the boat was great and a bunch of learning....I am looking forward to next may!  Thank you for your continued support.

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