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  1. #1
    Member
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    Jun 2010
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    Vidalia
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    48

    115 optimax prop question

    I have a 2005 115 optimax engine on a 2001 Nitro 17.5 foot boat. When the livewell is filled up, I have no hole shot at all. I have tried a couple different things to improve this with no success, changed motor mounts, added a hydrofoil, and have had it serviced by a mercury mechanic. I'm wanting to try a different prop now, I have the same prop that it came with when I bought it. It is a renegade 3 blade stainless steel prop, the pitch from what I've been told is a 20. I was told to not go less then an 18 pitch.

    My original idea was to buy an aluminum prop to see if the different pitch works before spending the money on a stainless prop. It seems like there are different size props also, as well as 4 blade props. Any insight on this would be great, and if you suggest a prop can you give me all the specs so I know exactly what I'm looking for.

    Thanks

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
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    94,941
    #2
    First suggestion I would make is to try to stick with Mercury propellers.

    Mercury has a Prop Selector that you can plug in the information from your boat, and it will output a few different props that might work well. The "renegade" isn't a lot of help as you're not 100% sure of it's pitch.

    Some other things you need to know with ROCK-SOLID info before you start buying props:

    1. WOT Engine RPM's.

    2. WOT Water Pressure

    3. GPS Speed at WOT

    4. ACTUAL pitch of current prop (or the very least, the part number).


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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  3. Member
    Join Date
    May 2020
    Location
    Huntsville, Al.
    Posts
    2
    #3
    I have a 2006 115 Optimax on a Triton TR176. What helped me was prop to pad height, and using the Mercury prop selector. I ended up going to a 4 blade prop. My 4 blade that I use is a Mercury Trophy prop, 21 pitch. My prop to pad is 4 inches, but I believe it can go higher for better holeshot performance. If I have fish in the livewell, before I start running,I will drain the water in the livewell tank down to a little above half. It takes about 3 to 5 seconds more to come out, but comes out and runs at about 48 mph. This is with two people that are about 200 lbs, fuel tank a little over half full. No plugs in the prop, RPMs are about 5600 - 5650 at WOT, water pressure at WOT is about 10 to 12 psi.I'm in the process of trying one large plug in the prop to see if it will come out of the hole a little better, but I will also probably raise the engine about another 1/4 inch to see if it comes out better with the large plug installed.
    Last edited by olskool; 03-29-2021 at 08:24 PM.

  4. Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
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    13,938
    #4
    would also check in NITRO boat forums for others with a boat like yours
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member
    Join Date
    Jan 2020
    Location
    South Point OH
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    5,363
    #5
    A 19" pitch Mercury Spitfire X7 does very well on that motor on the aluminum Ranger and Trackers, good hole shot and around 50 mph top speed.

  6. Member
    Join Date
    Jun 2013
    Location
    LONGVIEW TEXAS
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    13,938
    #6
    there ya go
    .................................................. ...the scariest thing in life is the unknown ...................................