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prop size mako 25

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  • prop size mako 25

    to anyone running a 70's mako 25 cc with a single engine 225-250 Hp I would like to know what size prop you are running and what your #'s are. thanks
    [br]Burlington , MA[br]Previous Boats[br]25\' Mako CC 225 Yamaha (sold)[br]30\' Grady Marlin T/250 Yamaha\'s (sunk) [br]Current boats [br]10\' Zodiac 8hp Yamaha[br]15\' Whaler 75hp Merc[br]24\' Wahoo! EFS 250hp Merc[br]

  • #2
    We have a 1978 Mako 25 with a 225 carbureted mercury and a 17 pitch prop and the WOT rpm's are 5300. With the boat lightly loaded we can get about 40 mph. At 4500 we cruise at 33 knots.
    Patrick[br]Biloxi, MS[br]1965 Bertram 20[br]1998 Action Craft SE 175 VMAX[br]Looking for a 1976 Mako 25 CC[br]

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    • #3
      My father has a '79 25'. Had a 250 (carb.) Yamaha w/ 19" Steletto. WOT 44mph @5400

      Now has 300 Yamaha HPDI with 19" Yama Salt Water Series Prop WOT 50mph @ 5400

      Cruise @ 41k 37-38 mph!!!

      Not sure the exact ratio, but the 300 has a Much taller gear.

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      • #4
        Thanks for replying do you run with a T-top ? How much fuel? Trim tabs? You guys #'s have me beat by alot. I have a carbed yamaha 225 with a 13 3/4 x 17 SS and get about 23 knots @ 4200. I don't run much more rpm than that as to keep stress off of the engine. I don't have trim tabs . I do have a T-top (hard not fabric). Appoximatly 70 gallons on board, 2 people, usual fish gear on board
        [br]Burlington , MA[br]Previous Boats[br]25\' Mako CC 225 Yamaha (sold)[br]30\' Grady Marlin T/250 Yamaha\'s (sunk) [br]Current boats [br]10\' Zodiac 8hp Yamaha[br]15\' Whaler 75hp Merc[br]24\' Wahoo! EFS 250hp Merc[br]

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        • #5
          T.R. #'s are with trim tabs, without T-top, 50 gal. fuel, and 2 guys. I would think that with a 225hp, 17" is as big as you will be able to turn. Besides that try as many props as you can get your hands on.

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          • #6
            Our readings are without trim tabs and about 130 gallons of fuel. The only way that you can figure out how your engine is running is to go ahead and max out the engine and see what the WOT rpm's are. This is very important because you might already be stressing your engine from running it too hard. I would imagine that a 17 pitch prop is what you need if you are planning on bringing a good amount of fuel and people on your trips. If your boat is lightly loaded all of the time you might be able to get away with a 19 pitch. You want your rpm's to be between 5200 and 5600. Every degree of pitch that you change on your prop should be about 200 rpm's. It sounds like your actual problem is that the carburetors should be rebuilt. If the high-speed jets become clogged, then they don't allow enough fuel to run it at high speeds. Older yamahas don't typically have as much power as a mercury. With it all working correctly you should be cruising at about 30 knots at 4500 rpm's.
            Patrick[br]Biloxi, MS[br]1965 Bertram 20[br]1998 Action Craft SE 175 VMAX[br]Looking for a 1976 Mako 25 CC[br]

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