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Thread: prop help

  1. #1

    Default prop help

    I have bought a 18 ft. pontoon with 1999 merc.50 that runs great,it has alum. prop F10.13x15p, on the foot is a sticker that says 12x22 1.83:1,
    At wot tach is showing 4200 rpm. and gps shows 17.3 mph. Sticker on engine says 5500 rpm, It is time for a new prop and looking for advice on what to use, Being a man I would like more speed,but I do not pull tubes or anything,used solely for cruising,I am looking to do what is best for my engine.Thanks for help.

  2. #2
    Join Date
    Apr 2016
    Location
    barnegat NJ
    Posts
    2,706

    Default Re: prop help

    Is tach accurate,thats alot of boat for that motor,a less pitched prop will give higher rpms and less carbon buildup in engine,and longer life on same,

  3. #3

    Default Re: prop help

    as far as I can tell tach is accurate,there are 18 and 20 ft. pontoons everywhere here with 50 h.p motors, I was thinking of probably going with 11" pitch, but not sure.
    Looking for input cause I certainly not expert, Thanks

  4. #4
    Join Date
    Apr 2016
    Location
    barnegat NJ
    Posts
    2,706

    Default Re: prop help

    ask other boaters what pitch& diameter there using with same hull&motor.according to theory 1 inch of decreased pitch will give approximately 100 rpms.

  5. #5

    Default Re: prop help

    11" pitch sounds a good idea , depending on the load of the pontoon. Empty I would sggest 121/2" which should bring the motor better to live and increase speed.
    13" diameter is also a lot for that motor!

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