Quote:
Originally Posted by drtyTshrt
FF I have a 20ft center console with a 400lb 200 Merc with a worn out 14" 19 pitch SS prop and get 48 at WOT bout 6800 RPM.
I need a new prop and I would like your suggestions.
I have been told the bigger diameter props for the 2.5 liter and four strokes are to big for my 2.0 liter.
I want to be in your range 48 mph at 2/3 throttle.
I know with my prop being worn so bad is increasing the RPMs a lot but I also think I may can do a 21pitch.
Suggestions please.
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I would prop to the next pitch to get you rpms down some if you don't normally run heavy loaded sometimes and also stick with the small dia props 14.5 inch or so. The 2.0s don't like the big 15.5 inch plus cupped wheels so well. My 200 is a modified 2.5 with an aftermarket Brucato computer box and some other mild items done to it. Nothing to rad but it may put out 220-230 hp or so vs a standard 200. I found out for faster top end speeds the smaller and lighter 14.5 inch props with give you more MPH. The mercury 40 or 41 series style are lighter and faster than the newer 44 or 45 Plus series with vent holes. The mirage plus props at 15.5 do much better far as handling, keeping on plane, lifting the rear and cupping the water in ruff conditions but will lose you 3-5 mph. Like mentioned I have ran chopper surface props and also the rev four mercury prop, getting you motor height right and the lower unit out of the water so the AV plate is visible while under way not dragging will help you more than most props as you don't have the drag. You may pick up more with adjusting the motor than changing props. Also my hull is super light with only the necessities, less that 30 gallons of fuel and no seating or any other add-ons. I never finished out the hull as I started other projects so how much you load the hull will effect you too. Start with getting you motor height right, get the right pitch to match RPMs so that you can hit max limit or slightly above with your self and normal load, then you can try different prop types. The 3 vs 4 blade you may need different pitch as a 19 four blade may act as a 17 three blade. Also try to move weight forward and balance the boat out best you can.