Southport 29 Repowered with Suzuki Twin 250 APs

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  • Southport 29 Repowered with Suzuki Twin 250 APs

    Repowered over the winter with the Suzuki 250s which replace Yamaha F250s. First I will say that once I manage to get the boat out of the hole it seems to run nicely. The issue I'm struggling with is getting it OUT OF THE HOLE If I accelerate from idle slowing through the range the boat starts to climb out but the props both slip out and rev up high to point I have to shut down again. If I throw the throttles forward VERY quickly the boat will climb out, but lose the props again for short period and then catch themselves and dig in and take off.

    Neither of these scenarios is what I would expect to be normal operation. Having just dropped the boat to the installer for the 20hr and on word from the Southport factory they rig these motors on the 2nd hole from the top I had them lowered a hole since they were mounted on the 3rd hole and appeared a bit high when I checked the boat out of the water. Issue still exists per their testing yesterday.

    I'm heading their tonight to gather some of the performance numbers but not sure if that will help as once the boat finally gets on plane all seems to be wonderful with them. I just struggle getting this fat girl OUT of the water at takeoff.

    Stats i have so far are motors mounted on 2nd hole from the top of the mounting bracket and the props are the Suzuki 3 / 16 / 18.5 . As expected this occurs less with the boat lightly loaded but with full fuel and 3 of us aboard for a recent contest it was a real challenge getting the boat out of the starting gate.

    I'd love to ask the experts here their thoughts on what would be best next steps?? Installer mentioned perhaps having the current props cupped. I asked about maybe more pitch. ?? They did not feel adding pitch would help, is that accurate ? When I signed I asked them about possibly using 4 bladed props but they felt that shouldn't be required. I wonder if it might be something needed now ??

    I would GREATLY appreciate any insight or education you folks may be able to offer here

    thank you in advance,

  • #2
    Best thing is to wait and see what your results are tonight. I agree that more pitch is not likely a good approach and that 4-blades should not be necessary.

    Comment


    • #3
      Sounds to me as if you have a prop problem.. Rake not right.. Dumb question but, they did give you the 25 inch shafts, right? Sounds to me like you are blowing out, either from mounting too high or props are not properly sized..

      A 4 blade prop will give you a lot more bite and stern lift..

      Maybe Ken will comment..

      Comment


      • #4
        I'm having similar issues with 300APs running the same prop. We have an ass-heavy Proline 2950 repowered in 2018. Was porpoising and cavitating after the repower, so we raised the engines 1 hole. Make a big difference but still have problems when loaded. When offshore, I have to bury the tabs and run at least 30 mph to stay on plane. Not fun in a heavy chop. I'm thinking of going with 4 blade props for more stern lift. I'm not worried about top-end speed, as we are primarily fishing offshore. Hopefully Ken will weigh in on this thread, but I'm going to call him for some advice.

        Comment


        • #5
          Originally posted by KMac View Post
          Sounds to me as if you have a prop problem.. Rake not right.. Dumb question but, they did give you the 25 inch shafts, right? Sounds to me like you are blowing out, either from mounting too high or props are not properly sized..

          A 4 blade prop will give you a lot more bite and stern lift..

          Maybe Ken will comment..
          Yes, the motors are the 25 inch models for sure.

          Comment


          • #6
            It is common to have the ventilation issues with Suzuki motors. Many times you just have to run them a little lower then you may have run motors of some other brand.
            The AP's especially.
            Adding some cup to your existing Suzuki props might be a big help and doesn't cost much to try.
            The other option is a more aggressive 3 blade, or a big 4 blade.
            The Mercury Enertia ECO is a big 16 inch diameter 3 blade that normally has a little better traction then the Suzuki prop, may solve you problems, and keep your top end up.
            The Powertech LFS4 is a big 16 inch diameter 4 blade. They are the ONLY 16 inch diameter 4 blade available. It has good traction, gives good sternlift, and will likely solve your issue. but you'll probably give up 1-4 MPH on top end.

            On a side note, I've had a couple guys independently experiment with the engine alignment on their suzuki's.
            Both ended up with the motors toed out about 3/4 of an inch. Said it helped a little, and didn't ventilate as easy.
            To avoid confusion on toed out vs in.
            When I say toed out, I mean tips of the prop shafts 3/4 of an inch closer together then the tips of the bullets.

            Ken Reeves
            KR@Propgods.com
            941-735-5808

            Comment


            • #7
              Originally posted by Maybe Tonight View Post

              Yes, the motors are the 25 inch models for sure.
              I figured they were.. It has to be a prop issue.. I hope Ken will see this.. I will PM him with the link to this topic..

              Never mind... He has arrived..

              Comment


              • #8

                Thanks you all for the replies, appreciate the input for sure

                To follow up on what I saw running the boat last night. We confirmed the blowouts still happen when taking off out of the hole. The slow and steady acceleration NEVER lets me get the boat up as the props let go as soon as she starts climbing up. PUNCHING the throttles forward quickly jumps the boat up, the props break loose for several seconds and then dig in and off she goes.

                GPS numbers I had last night, at 4100 rpm hit 32mph , 5300 hit 42 mph and WOT best I got to on the tach was just under 6000 and was at 47mph. My bay was not rough by any stretch but wasn't glass calm either, these numbers were running straight into the breeze (and chop). The top end is seems down 100-200 rpm with the motors being dropped down a hole which i understand is to be expected.

                So, no resolution to the blowouts by lowering the motors, back to square one again

                Comment


                • #9
                  LFS4 would be a safe bet. tough call between 18 or 19.
                  I'd probably go 18 pitch if you were under 6000 RPM with your 18.5 Zukes.

                  Ken Reeves
                  KR@Propgods.com
                  941-735-5808

                  Comment


                  • #10
                    Originally posted by ken2 View Post
                    It is common to have the ventilation issues with Suzuki motors. Many times you just have to run them a little lower then you may have run motors of some other brand.
                    The AP's especially.
                    Adding some cup to your existing Suzuki props might be a big help and doesn't cost much to try.
                    The other option is a more aggressive 3 blade, or a big 4 blade.
                    The Mercury Enertia ECO is a big 16 inch diameter 3 blade that normally has a little better traction then the Suzuki prop, may solve you problems, and keep your top end up.
                    The Powertech LFS4 is a big 16 inch diameter 4 blade. They are the ONLY 16 inch diameter 4 blade available. It has good traction, gives good sternlift, and will likely solve your issue. but you'll probably give up 1-4 MPH on top end.

                    On a side note, I've had a couple guys independently experiment with the engine alignment on their suzuki's.
                    Both ended up with the motors toed out about 3/4 of an inch. Said it helped a little, and didn't ventilate as easy.
                    To avoid confusion on toed out vs in.
                    When I say toed out, I mean tips of the prop shafts 3/4 of an inch closer together then the tips of the bullets.
                    THANK YOU KEN for your reply here. My installers mentioned possibly cupping the current props while I was there last night. May I ask you to expand on the "more agressive" Mecury prop. That mean it's more pitch on it ? That Powertech prop you mentioned sounds interesting as well but not sure I'll get buy in from the installers as they are totally worried about making sure the motors hit the recommended RPMs, almost their SOLE concern. Every conversation so far ends up back on that point.

                    If I went to that LFS4 16 inch prop what would be the expected estimated loss of the WOT RPM ?? just would like to add as much ammo to my kit as I can on this to push these guys.

                    Thank you in advance SOOOOO much!!!!!

                    Paul

                    Comment


                    • #11
                      Ken, one more thing, would I be correct that if i were to go for the LFS4 prop that I would be able to get them from you ???

                      thanks again sir

                      Paul

                      Comment


                      • #12
                        Originally posted by Maybe Tonight View Post

                        THANK YOU KEN for your reply here. My installers mentioned possibly cupping the current props while I was there last night. May I ask you to expand on the "more agressive" Mecury prop. That mean it's more pitch on it ? That Powertech prop you mentioned sounds interesting as well but not sure I'll get buy in from the installers as they are totally worried about making sure the motors hit the recommended RPMs, almost their SOLE concern. Every conversation so far ends up back on that point.

                        If I went to that LFS4 16 inch prop what would be the expected estimated loss of the WOT RPM ?? just would like to add as much ammo to my kit as I can on this to push these guys.

                        Thank you in advance SOOOOO much!!!!!

                        Paul
                        No offense, but I would take what they are telling you as opinions. That’s what they are. They haven’t offered any real insight on how to correct the problem. As installers/dealers, their sole goal should be that you are happy with your purchase and the performance is as advertised. Who cares if the props are turning up if they aren’t biting and keep blowing out??

                        I would definitely give them the information Ken has shared and see what their intentions are.

                        Comment


                        • #13
                          Mechanics want the motors to start, and hit the right RPM, they don't particularly care how the boat handles.
                          If they are only able to work with Suzuki props, RPM is all they have to work with. There isn't' another suzuki prop that is going to fix your issue.

                          By more "Aggressive" I mean, it has better traction then a stock Suzuki prop. You need more traction.
                          your props are breaking loose, ventilating, loosing traction, slipping, however you want to describe it.

                          You need a more aggressive prop, or more bite, more traction,
                          End goal is for you to roll up on plane without ventilation.

                          Ken Reeves
                          KR@Propgods.com
                          941-735-5808

                          Comment


                          • #14
                            Sorry for the thread hijack. But are you the same Maybe Tonight that posts the fishing videos on utube? If so good videos with good fishing advice...Charlie

                            Comment


                            • #15
                              Well that sounds cool, got a link to that ?

                              Ken Reeves
                              KR@Propgods.com
                              941-735-5808

                              Comment

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