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Need help deciding on a prop!

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  • Need help deciding on a prop!

    Hello everybody I’m new here! I just purchased an ‘86 Stratos 179v with a 110 Johnson on it and need help deciding on the best prop for my boat! Any help is greatly appreciated!

  • #2
    Lots of things need to be known up front such as current prop, current prop size, current top speed (@ a given rpm), etc.
    1990 Wellcraft Eclipse 196
    Mercruiser Vortec 4.3 0M322285
    Alpha gen 1


    • #3
      I haven’t had a chance to put the boat in the water yet because it is winter here, but I’ve had the motor running on muffs and have done a lower unit oil change. I believe the prop that’s on it is 14” with an 18 pitch but from the research I’ve done it seems like a steeper pitch would give more top end speed. The reason I’m searching for the best prop size is because the one on it is just an aluminum one and is pretty chewed up so I figured I would replace it with a stainless prop before it’s time to do some tournament fishing!


      • #4
        You need some baseline data, but propping for more top end speed might make the performance unenjoyable in the rpm range that you actually use it in. I prefer huge low end grunt for pulling skiers and giving up a little top end where I never operate anyway.


        • #5

          I contacted the old owner and he said that with the 14” 18 pitch prop it would do about 40MPH as a top speed, he wasn’t positive on what RPM it was turning though. The motor is an 87 (I believe) 110hp Johnson VRO so I’m not sure what the “sweet spot” for the engine would be either. I’m looking more so for top end speed but also don’t want it to be a dog at takeoff! Hope this added info helps in finding quality answers for me! Thank you in advance!


          • #6
            You need to run first to determine if you even need a different prop. From what i found here,
            an 18p prop sounds about right for all around purposes, Of course all this depends on engine mount height, type use, load, etc. if you're looking for max speed, start with engine mounting height first. Improperly mounted engines can cost you up to 20% in speed and fuel efficiency.


            • #7
              Lesson in physics: You (nor us) cannot determine what you need in a prop because you have not yet determined if there is an actual problem. What you have may have been optimized and anything you do can actually harm performance. As suggested, dunk the boat, run it wide open throttle with what you consider an average load. If the engine cannot reach or get close to the upper end of the recommended RPM limit, you would need to go down in pitch. If it tends to over rev with that load, you can go up in pitch. But before looking for props, make sure the engine is in perfect operating condition. Changing props is a waste of money on an engine that is down on power do to age, wear, abuse, or poor state of tune. A water logged boat has an "overweight" issue and affects performance as well. A different prop cannot fix these issues..


              • #8
                As far as the prop being "pretty chewed up" that can mean different things to different people. Take a file and smooth the edges down and give it a test run as others have suggested. See how the boat handles, hole shot, and of course, gps speed and a reliable RPM reading at WOT. After that, choose what you would prefer in the boat, top speed or hole shot and go from there. There is no purpose in throwing money at new props for the sake of having a new prop on a new to you boat.


                • #9
                  Sign up today
                  Ahhhh the old Stratos 179V submarine!!! Built right in my backyard by Mr Earl. On a hot day fishin, trim the motor out about half way, speed about 30MPH and veer sharp to the left. Nose will drop and dig, rear end will raise and passenger will get a nice cool wave of water!! Quick way to wash carpet also. Boat will handle better with a bigger motor .
                  When in doubt,Trim it out!!!
                  Business Owner & Certifed Technician
                  Boats I own & use
                  20ft Javlin w/250 Junkrude
                  17ft Bullet w/200 Merc (SOLD!!)
                  13ft Allison w/150 I-6
                  17ft Hydra-Sport 175GT
                  15ft Allison w/75 Stinger(project)
                  14 x 48 Drifter with 1100SS Merc