www.iFourWinns.com

Ok, I'm a newbie when it comes to this. How do I know what the safe RPM range is for my boat? I can't find it listed in the manual. How is that affected by changing to a different propeller? I have a 2007 Horizon 210 with the carbureted 5.0 Mercruiser. I have the Alpha 1 outdrive and currently have a 21p 3 blade aluminum prop. I'm looking at changing to a 19p 4 blade stainless steel prop. I only run my boat at WOT when getting on plane, then back it off, but I'm not sure how many RPMs are too much and how many RPMs are too little. I certainly don't want to wear out my motor.

Thanks!

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2007 Horizon 210
5.0 Mercruiser Carbureted/Alpha I

Page 28.

http://www.fourwinns.com/uploads/2017/2 ... ts2007.pdf

This might help with understanding props. It helps if you visualize it spinning as it moves through a solid object:

http://www.boatingmag.com/how-to/unders ... ller-pitch

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Mike
2005 Four Winns 230/240
VP 5.7GXi/DP
1998 F-150 XLT
Boat Pic

I must be blind, I'm not seeing the recommended/max RPM range. Also, that says I should be going 47mph at 4500 RPM. On a perfect day I might hit 41 at WOT trimmed up. Should I take that to mean something is wrong with my boat?

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2007 Horizon 210
5.0 Mercruiser Carbureted/Alpha I

If your current 3 blade prop allows you to hit max RPM the 4 blade you have selected should give you the same. You must go down in pitch when adding a blade.

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2008 H200 Frenzy Edition 5.0 GXi

1993 Horizon 190 5.0 EFI (Sold)

4400-4800 RPM.

https://www.perfprotech.com/blog/tech-s ... ifications

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One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy