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4 Blade prop or a 3 blade prop on a 14' jon boat....

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  • 4 Blade prop or a 3 blade prop on a 14' jon boat....

    I was curious right now i have a 15 hp 2-stroke mariner, owner said 1448 but it measures 41 so it is a lowe 1442 or a 1440 mod-v. Right now motor has a 9-9 prop its scratched up on blades and one fin is slightly bent just a little but it is bent, with 2 people it seemed to captivate a little not much in the hole shot department. But it would fly i should have brought my gps but i forgot it, had to be going 22-30mph, question is since i had no gear wouldnt that get worse with more gear, it almost acted like tires slipping on ice if you get my drift. Dad thinks maybe prop is slipping it didnt sound like it but if i got a new prop it would come with a new prop slipper lol whatever it is called..

    So question is has anyone switched to a 4 blade and had good results or like it way better so from what i have read is to match prop now i would go to a 4 blade 9-8 and since it is a 4 blade i should get better hole shot and the same speed????
    I dont know i will be in rivers so i want it to have a good hole shot and speed thanks for the advise.

    And forgot anyone used a hydro foil wing has it helped or is it a joke?


  • #2
    Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

    I don't think a 4 blade prop is available for a 15hp. why not get that prop rebuilt.

    Comment



    • #3
      Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

      If you could find a 4 blade prop in 9-8 it would probably improve your hole shot but you would pay a price in top end because 4 blades would produce more drag.
      sigpic

      Comment



      • #4
        Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

        To answer the part about the hydro foil being good or bad.I have a 25 hp Merc on a Grumman 14 footer and I could never get the boat trimmed enough to plane with just me in it.I added a whale tail stabilizer plate and the boat will jump on plane immediately with one or three people on board.Top speed is 30-33.

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        • #5
          Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

          Depending on the year their are a few 4 blades around but it is a limited selection, I am also looking into a 4 blade my self, also have a 15 hp mariner, but you really need to know what your RPM`s are before you get into changing props out.
          sigpicJames & Deb

          Bad Dog

          If it aint broke your not having enough fun

          my 1988 Riviera Cruzer pontoon rebuild
          http://forums.iboats.com/showthread.php?t=526820

          Comment



          • #6
            Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

            Hey hawker whats up you helped me on my mariner fuel problem its fixed now, I was just curious i seen a couple of 4 blade and thought hey it would get better traction. I have no idea what the rpm are it sounds right too me I just wonder if i go too a 9-8 3 blade if I am going to lose alot of top end....I dont know what to do I dont know if i get a new 9-9 3 blade with no knicks and will have a better exaust port if that will make a difference??

            And i have fount a couple of 4-blade in 9-9 and 9-8, because of the 4 blades from what i have heard in order too match your 3-blade you go down a size, what if i got a 4-blade in 9-9 i should get the hole shot and more speed would that be correct i just dont want problems planing on a river with all gear in the boat..

            and for prop rebuild i guess i could clean it up myself but there is no place around here for that plus, new 4and3 blade props for my motor are $48-67 ALUM would cost a arm and a leg to send it off to be re-done...

            Comment



            • #7
              Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

              Solas makes 3 and 4 blade props for your motor.

              It would help to know what year the motor is.
              Have a nice day!

              Comment



              • #8
                Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                I know which prop works with my motor i just dont know which is the best one.....It is a 1996 15 hp short shaft mariner. Boat is a 1442 lowe mod-v jon boat will have 2 ppl plus gear.

                Comment



                • #9
                  Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                  I am far from a prop expert but the basics are this so I will explain a bit about it.

                  The prop limits the max RPM your motor turns at wide open, so to low a pitch and it over speeds the motor and to high of a pitch and it bogs it down and you dont get full HP. a 3 blade has faster top end and a 4 blade has a better hole shot but you lose some top end.

                  So when messing with props you have to be very careful you cant guess you have to know, to low of a pitch and you can over wind the motor and fry it. You really really have to know what your WOT ( wide open throttle ) RPM`s are before you start making changes and as you are seeing props aint cheep.

                  You mentioned it has a 9-9 scratched on the blade, take the prop nut off and find the number and make sure its a 9 P thats 9 pitch then get a tach and see what its turning, and once you know that then you can think about a new 3 or 4 blade. I would hate to see you fry your motor.



                  You can pick up a test tach cheep a common one people use is called tiny tach.
                  Design Technology, Inc., Home of Tiny-Tach
                  sigpicJames & Deb

                  Bad Dog

                  If it aint broke your not having enough fun

                  my 1988 Riviera Cruzer pontoon rebuild
                  http://forums.iboats.com/showthread.php?t=526820

                  Comment



                  • #10
                    Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                    delete

                    Comment



                    • #11
                      Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                      Before any prop change you need to get your wot rpm and gps speed.Its the only way to be sure your setup is working and what it might need to be right. For the health of your motor and best performance you need to be sure the motor is operating within its rpm range.Some cells have a gps app.It is very likely that a new 9" prop will work perfectly. Your boat and typical load is certainly reasonable for a 15. A new prop should out perform your beatup prop without question.

                      Comment



                      • #12
                        Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                        Ok cool yea i forgot to bring my gps sat to test speed, I dont want to spend $50.00 plus ship just to test rpm's the prop that is on it looks factory im probaly just going to order a new 9-9 it should have a better exhaust port i guess ill just order that one thanks guys....

                        Comment



                        • #13
                          Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                          You can get one off of e bay for under 20.00 including shipping. A friend of mine got one for 12.00 including shipping.
                          sigpicJames & Deb

                          Bad Dog

                          If it aint broke your not having enough fun

                          my 1988 Riviera Cruzer pontoon rebuild
                          http://forums.iboats.com/showthread.php?t=526820

                          Comment



                          • #14
                            Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                            Keep in mind that the tach will work on any motor land, sea or air 1 cylinder or 16 if you figure in a little math on motors over 8 cylinders.
                            Can be permanent or hand held.

                            Comment



                            • #15
                              Re: 4 Blade prop or a 3 blade prop on a 14' jon boat....

                              Ok i just bought a digital spark plug wire tester, there was a laser one but i dont see how it would be accurate because if you put it on a car tire with a small wheel and test it you would have lets say 3000rpm then you put on a bigger tire at the same throttle it would have to read lets say 2500rpm because even though motor is at the same throttle that little tire will be going faster than the bigger one, kinda like what your speedometer does when you put on bigger tires.

                              I dont know if that makes any sence to you guys but i thought the laser one wouldnt be accurate on the flywheel hopefully the spark plug one will be more accurate, it is coming from cali so i wont get it until next week.

                              Would anyone know on my motor 1996 mariner 15 hp perfect RPM would be, after i get it i will take boat out the next weekend and give you guys the results....

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