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Thread: 1996 Mercury 50 4 stroke prop suggestions

  1. #1
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,204

    Default 1996 Mercury 50 4 stroke prop suggestions

    I am going to alter from my norm and actually buy a prop for this motor on my boat. I have a 3 blade aluminum 13p on it now, and it seems ok. I do not have the tach hooked up, but I will before I buy the new prop, so I can see where I need to be on pitch to hit the 5500-6k range. This is the 1.83:1 small gearcase. I'm loing for a tested prop that works well on these small case midrange 4 strokes, or even on a small case 2 stroke. I'll probably stick to aluminum, since I'm in shallow water a lot, and I'd rather buy props than gearcases.

    Any and all suggestions are welcome.
    2006 Forester 19 Fish (new deck and carpet, Pontoonstuff interior, 2019)
    1996 Mercury 50 ELPT4S
    1983 Sea Nymph FM171 Striper (complete rebuild from hull up, 2014)
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

  2. #2
    Join Date
    Feb 2014
    Location
    Boat at Lake of the Ozarks Missouri
    Posts
    602

    Default

    Hey Larry:
    You know, above many others, that you can't get where you want to go unless you know from where you start.
    A successful propping outcome relies on where you are now and what you want to achieve. So lets look at the basics.

    Your boating knowledge is above most and it's good that you know the gear case ratio along with the WOT max RPM range for your engine.

    So here's what we don't know; what is your top WOT RPM now with the 13p aluminum ? What speed are you running at the
    current WOT RPM ? And most importantly, what are you looking to gain ? RPMs no doubt and maybe top end.

    What is the weight of the rig with 1-2 persons, 1/2 tank of gas @ 8lbs. per and all the gear you would normally
    have on board when you go out for a run ? Including the cooler with a 6 pack in it ?

    Once you get that tach hooked up and know these numbers you can decide on which way to go.
    If you need RPMs and the speed is just ok then go with a smaller diameter with the same pitch.

    By the way, what dia is that 13p prop ? If you have the WOT manufacturers range when the tach
    is hooked up and you need more top end, then change pitch with the same diameter.

    Just remember that the pitch and diameter are sometimes a cooperative pair, I.E. a small pitch change may only
    be available within a diameter change as many manufacturers offer only odd sizes in dia when going up in pitch.

    Get the numbers and then do the prop selector chart on Mercury's web site. Tell us what you have
    and where you want to go. Good luck .
    Captain Tony
    2005 Summit by Triton - 220T Platinum 3Log
    2005 115HP Mercury Optimax - 228 Marine Master Trailer
    St. Louis & Lake of the Ozarks, MO.

  3. #3
    Join Date
    Jun 2004
    Posts
    6,205

    Default

    I would start with a 11" pitch and go from there Larry..
    Rick

    St. Louis/Lake of the Ozarks

  4. #4
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,204

    Default

    I appreciate the input guys, I know I want to turn the biggest diameter prop it will take, at about 5800 WOT loaded down pretty heavy. With the 13 and lightly loaded it will hit 20 mph with a little wind behind it. I'm really looking for a recommendation on a brand name or type that someone has tried and liked on a mid range motor. I bought a 4 blade Comprop and had it on the Tracker with a 75 and really liked it. If no one here suggests a favorite, I'll probably go 4 blade aluminum or Comprop.
    2006 Forester 19 Fish (new deck and carpet, Pontoonstuff interior, 2019)
    1996 Mercury 50 ELPT4S
    1983 Sea Nymph FM171 Striper (complete rebuild from hull up, 2014)
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

  5. #5
    Join Date
    Feb 2014
    Location
    Boat at Lake of the Ozarks Missouri
    Posts
    602

    Default

    Hey Larry:
    You might know from some of my previous posts to forum users that I am a big supporter of four blade props for their extra hole shot and holding in the turns.
    I think you can swing a 4 blade but be aware that you will have to drop down on pitch because you will loose between 200 to 400 RPMs by going to a 4 blade.

    So if you are trying to get to the 5800 RPMs you might try am 11 pitch with a 1/2 smaller diameter than the 13p you have in the 3 blade.
    The best bet is with Mercury's Spitfire in aluminum with cupping. Do the Merc. program on their web site with your known specs.
    Captain Tony
    2005 Summit by Triton - 220T Platinum 3Log
    2005 115HP Mercury Optimax - 228 Marine Master Trailer
    St. Louis & Lake of the Ozarks, MO.

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