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bigtoldaddy

I have a 97 17ft Sport Proline (boat/moter)with a 90hp Johnson on it. I'm running a 13 x 17 pitch prop on it and at WOT I get 30mph and 6400rpm on the tack.   My questions are, Should I go to a 19 or 21 pitch to bring it down to the 5500 rpm range?  And is it better to step up to a 14 inch diam. or keep it at the 13?  Will It cavitate more with the 13 or 14 inch?   Thanks for any help.

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outboardwizard

Hello, First verify that your tachometer is working correctly (Example make sure idle rpm is 700 in gear)...If ok I would go to 21 pitch;  (Don't be concerned about propeller diameter because it changes as prop pitch increases).

I would suggest either SST or Viper- both props will work the same - Viper props are polished version. 

If you want to run a high engine height, you should use the 20 inch (pitch) OMC Raker, for superior top end.

 

Check out our V4 Prop chart on website - Consider using OMC – Bombardier Viper Part Number 177261 (13 7/8 x 21), or Raker P/N 394759 (13 1/2 x 20).

If you prefer SST props, consider using P/N 176574 (13 7/8 x 21).

 

 

Article How to Chose The Best Propeller has some more tips/info.

(Note – Website charts, pages, prices, etc. are currently being updated/revised – If you can’t locate the above prop numbers on chart, call me on Cell – 631-514-1525, or check back to the website in a couple of days.)

 

Ralph

Ralph, The Outboard Wizard
Owner, Lindenhurst Outboard Service Inc. since 1979 +
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