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Another prop thread... Yamaha 40 2 Stroke

Discussion in 'Boats, Blinds, & Gadgets Forum' started by trst, Oct 23, 2020.

  1. trst

    trst New Member

    Messages:
    3
    Joined:
    Oct 22, 2020
    Just picked up a 99 Yamaha 40 tiller w Tilt and Trim for a 02 War Eagle 548LDV
    Current prop: Yamaha alum 10 5/8 x 12
    Motor mounted in top position plate even with the bottom of the hull
    33 MPH at 5450 RPM
    From what I can tell WOT rating 4500- 5500 so I'm at the top of the range
    About to order a new prop and looking to see if I'm thinking about this right.

    If I stay w Alum I could go up to a 14 pitch and drop revs to ~5100
    If I go to SS do I still move to 14 or only move to 13 or stay at 12?
    I'm reading mixed ideas on SS (more efficient but heavier...)
     
    Olfducker likes this.
  2. Mike0311

    Mike0311 Senior Refuge Member

    Messages:
    453
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    Aug 11, 2018
    I would do 12 or 13 if I was going stainless steel. I have a 35 mercury on a 2001 war eagle and top out at 29 on a good calm day. I just buy really cheap props for it, I'm thinking its about 25 dollars per prop and they hold up fairly decent in mud and logs. I chose to go with cheap props just because of the logs I go through, that way my prop provides a weak spot in the drive line and will hopefully go out before the gears or shafts do. I can usually get through a summer with one or 2 props and at that price I feel it is more than worth it.
     
  3. Aunt Betty

    Aunt Betty Elite Refuge Member

    Messages:
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    Sep 30, 2020
    Location:
    Champaign
    Find buddies that have similar rigs and do a prop day. Swap around and get hammered. See what makes your boat go best. I know they do that in arkansas . Find the boat club or whatever.
    Buying props gets expensive
     
  4. trst

    trst New Member

    Messages:
    3
    Joined:
    Oct 22, 2020
    I wish I had access to test props but not really an option at this point. I went with the alum props on my 25 and was 50/50 on the damage. My son hit a stump on step (OEM) and broke off a blade without any other damage. I hit a stump and bent a blade and the shaft (quicksilver). A possible compromise would be SS with a modular hub and hope the composite hub lets go before damage is done? My primary runs are in the deep river channel to get to shallow backwaters.
     
  5. Phytoplankton

    Phytoplankton Elite Refuge Member

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    Jun 26, 2008
    Location:
    CA
    You're currently running about as close to optimum as you're gonna get,what are you trying to accomplish with a new prop?
     
  6. trst

    trst New Member

    Messages:
    3
    Joined:
    Oct 22, 2020
    I was thinking it would be better to drop down from the max wot rpm to the middle of the range while picking up a little top end with the 14 pitch prop. I only have the prop that came with the motor so it would become the spare.
     

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