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How many RPM's is to many?

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  • How many RPM's is to many?

    I have a 1989 Evinrude 200 on my 20' and was curious about how many RPM's is to many. Should I really never go over 4000?
    24\' Scout w/ 225HP[br]20\' Mako w/ 200HP[br]17\' Bristol Skiff w/ 40HP [br]14\' Alumacraft w/ 15HP[br]MT Pleasant, SC

  • #2
    I think 4000 is cruise rpm on that motor and top end rpm should be around 5500

    Mike
    Mike[br]Milford Ct.[br]

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    • #3
      Actually 6000.

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      • #4
        I have a(1999)

        282 mako with twin 225 optimax,the propellers are MIRAGE 19 p

        and I'm curious about how RPM's are the ideal and how many RPM's is to many.

        Is the MIRAGE 19 p the right propeller for those engines ?
        Mako 282/T 225 Optimax \"NINGUNO\"[br]Menorca Island

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        • #5
          Dentx,

          Each engine manufacturer sets a max RPM range at WOT for a given engine. When an engine can get to that range, it is being worked at a proper load. If the RPMS exceed the max rating -- you're asking for trouble.

          Many conditions impact the max RPMs an engine will attain on a particular boat: Prop (the greater the pitch, the less RPMs the engine will reach at WOT), Load (3passengers and gear), bottom paint, T-Top (wind resistance), ...

          For example, my old Evinrude 225hp had a max RPM range of 5,500 - 6,000 RPMs at WOT. With a 15x17 SST prop, I could get 5,900 RPMs with 3/4 tank of gas and two large adults -- just about perfect. With just myself and a 1/2 tank, I could get 6,200 RPMs -- a bit too much. Had I moved up to a 14x19 SST prop, my max RPMs would probably dropped 3-400 RPMs at least. Max RPM range for the OMC 200hp was the same.

          For a Yamaha HPDI 200 or 250 or 225 EFI, max RPM at WOT was 5,500 RPMs. You did not want to exceed that.

          I now have a Yamaha 4-stroke F225 with a SWS prop, 14x17. Yamaha rates them to max of 6,000 RPM at WOT. With three adults, a 1/2 tank, T-top & bottom paint, I max my RPMs out at 5,800 and get 44 MPH -- again, just about perfect.

          Every engine/boat combo will be unique. Mercury has a set of spec's for your engine, I don't know what they are -- your owner's manual will tell you. If you cannot reach the recommended RPM range, you will need change to props with less pitch. If you're exceeding the max RPMs at WOT, you need to change out to props with more pitch.

          Good Luck,

          Prop Blast
          Prop Blast[br]Mako 224, F225[br]Tampa, FL

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          • #6
            Prop Blast , Thank you very much for the information.
            Mako 282/T 225 Optimax \"NINGUNO\"[br]Menorca Island

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            • #7
              dentex,

              My '02 carbed Merc. 150 has a small white sticker on the swivel bracket below the cowling on the stbd. side of the motor. On that sticker are the serial number and the max. RPM the motor should turn. You probably have the same sticker.

              For my engie, max RPM is 5600. With a 15 x 17 aluminum 3-blade I can get 5400 w/ a medium load in the summer time. Same load, same prop, but in Dec. when the air is 50 to 60 degrees cooler, I can get 5800.
              Brian[br]St. Leonard, MD

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              • #8
                Hi,gw204 !!,thanks for the information.

                My engines has the stickers too and they have mark 5750 rpm,the problem is that I cant run more than 4750 rpm (42 miles/hour).

                However,the Mercury service on my area will have a look to the engines tomorrow.

                Thanks again and excuse my english
                Mako 282/T 225 Optimax \"NINGUNO\"[br]Menorca Island

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                • #9
                  I agree with everyone but must stress how important it is that the engine have the ability to reach the max RPM's as specified by the manufacturer. Otherwise the engine is lugging. I think not reaching max is more harmful. I would not run it normally near max but check an average load to be sure you are propped right.
                  Former owner of a 1986 21B Mako[br]Venice, FL

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                  • #10
                    I agree 100%. I do not reccomend running anything WOT for very long, but your outboard should be able to spool up to manufactors reccomended max RPM easily. If it can't, it is lugging (working) way too hard and that causes heat....the death angel to outboards.

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