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  • 25 MAKO

    Im interested in buying a 1977 25' Mako deep vee boat, was rigged with twin mercs 20" shafts. if i buy the boat i want to rig it with a single yamaha 250, first ? is this enough hp for this hull, second ? the yamaha is a 20" shaft can this be changed to a 25" shaft to accommodate the hull,

    seaford ny[br]34\' Hatteras

  • #2
    QUOTE: the yamaha is a 20" shaft can this be changed to a 25" shaft to accommodate the hull.

    Yes it can. You will need a longer length driveshaft and either a longer case or case extension. I'm not sure, but it's not cheap to do.


    • #3

      A single 250 should push the boat at 21-22 knots depending on load and sea conditions. I have 2 friends with 25's; 1 is a 1978 CC with a pair of 140 4-stroke Suzukis and it is a nice rig. He can cruise at 21-22 knots and get 2 miles per gallon. He runs the NE canyons here in NJ on 94 gallons of gas. When it is calm, he will wind them up a little more and run 24-25 knots. She tops out at 30 knots. The other guy has a newer 25 walkaround with a single 250 and he gets decent performance numbers as well. He cruises 20 to 22 knots in decent weather with an average load. I am not sure of his fuel burn, it is probably 14 to 16 gallons per hour at cruise. Sea conditions are the common denomentaor in any rigs performance. My feeling is that 250 hp is the minimum power needed for the hull.
      Chris Miller[br]Mystic Islands, NJ[br]1974 17 Classic[br]1988 211 Classic (sold)[br]1990 Grady White 230 Gulfstream (sold)[br][img][br]


      • #4
        We run a 1977 25 Mako with a single 200 Johnson (1996). It cruises at 18 - 20 knots burning 12 gallons per hour at 4200 rpms in 2 to 4 foot seas. On calmer days we can run 4500 rpms and burn 14 - 16 gallons per hour and run 22 knots or so. Wide open at 5500 rpms we get close to 30 knots but probably do not reach it.

        We have been very happy with the performance of the boat although it is no speed demon. We have always felt that the early 25's we designed and built with a single installation in mind. However those numbers on the twin 140's are pretty impressive cgmiller.

        Columbus, Georgia[br]1973 Mako 17 angler \"Reel\'s Angler\"


        • #5
          With a pair of 150s on the back it tops out around 40 knots and cruises around 30 knots getting 1.5 mpg.
          Slidell, La


          • #6
            1. Can you "convert" a 20" shaft to a 25" -- sure, it's only money. Unless you can get a great deal on parts, I'm not sure it's worth it.

            2. Is a single 250hp enough to move the boat given a reasonable load -- yes. It won't be a speed demon, but it'll certainly get the job done. That configuration was very common. The other most common twin engine setup was twin 150's.

            Another option -- sell the short shaft 250hp, and repower with a used 250 someone is selling to put on one on of the newer 2-stroke or DFIs. Don't know where you are, but here in the southeast, folks are repowering left and right.

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


            • #7
              Aqua. I have that exact rig and have been toying with the idea of upgrading to a single 25" 300 hpdi. I have a 1977 cc with a t-top and 1993 250 yami. It is a great rig. No speed demon but you do not have to stop for anything. I get about 1.25 miles to the gallon and cruise at about 24knots at 4500 fully loaded. Think about the 300 hpdi. I bought this engine from a friend with the same boat upgrading to the 300 and he loves it. Much faster and more efficient. Let me know what you plan on doing. I will send you some pics.

              Rooster[br]1977 25CC[br]New Orleans, La[br][br]


              • #8
                rooster You are a brave soul or ginny pig as it were. Have you not read the problems with the 250 HDPI's? That's supposedly been fixed. They haven't fixed the 300 HDPI's yet.

                I just finished reading a 250 HPDI update. After all the upgrades the fellow has to spring for synthetic oil so it doesn't foul plugs.


                Here's a guy that has well over a $100K rig with them.[]

                Buck Wild

                Posted 10/12/2004 2:43 PM (#406325 - in reply to #406312)

                Subject: RE: 32' Regulator 300 HPDI's or 4 strokes Quote Reply

                Captain's Club Member

                Posts: 558



                Location: Atlantic Beach, FLI think the 300's would hurt your resale at the current moment. If and I mean IF Yamaha gets the bugs worked out of them and they prove to be a good motor I think that will be the motor of choice on that hull. Its comes down to how much faith do you have in Yamaha and can you deal with the problems of the 300's until they are fixed.

                FYI I have a 33' Palmetto Custom with twin 300's and they have serious problems at the moment.


                • #9
                  Thanks for the info. I did not know the 300's had such problems. I guess I will stick it out with my trusty 1993 250 Yami for the moment. Not really enthused with spending that much and having constant problems. My pics should be up soon. Just had the t-top put on pics to follow. Please forward any andvice you have on the new engines.
                  Rooster[br]1977 25CC[br]New Orleans, La[br][br]


                  • #10
                    I've got a 76 25' with t/130 yams I can cruise @[email protected]@1.8mpg fully rigged 175 gal. and 4 ppl aboard


                    • #11
                      I used to fish a 79 25 what went from twin 200 Evinrudes, to twin 150 Yamaha (almost same performance, less fuel burn) to a single 225 Evinrude. With the single it raised the water line in the rear about two - three inches and cut fuel consumption about 45%, but I never liked it. You had to give WOT to get on plane and you cruised at such a high RPM...and you didn't have an extra engine to get home on. It is an awesome hull with classic lines that you won't be dissappointed with, but twin 4 strokes would be the way to go IMO.
                      1978 Mako 25 - Blind Hog
                      1985 Mako 20c - sold
                      Fort Walton Beach, FL