Scandy White Tunnel, prop only gets 5300 rpm

Discussion in 'Props' started by Jwil, Sep 10, 2014.

  1. Jwil
    Joined: Sep 2014
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Georgia

    Jwil New Member

    Brand new scandy white tunnel boat with hydralic lift and Mercury 150 four stroke, prop is power tech OFX 17p 15 1/2 D 4blade. Can only get 5300 rpm and 41 mph top speed. I was told this boat should do 50 mph easy. I got a 4 blade prop for the hole shot as runing skinny is what it was made for, any help would be appreciated. Motor is rated for 5800 rpm
     
    Jwil, Sep 10, 2014
    #1
  2. CDK
    Joined: Aug 2007
    Posts: 3,324
    Likes: 148, Points: 63, Legacy Rep: 1819
    Location: Adriatic sea

    CDK retired engineer

    Two reasons:

    The engine needs several hours to run in, running full throttle is not the way to treat a new engine.

    A 4 blade prop has more drag than a 3 blade one. It can push heavier loads at mid range but the top speed is lower.
     
    CDK, Sep 11, 2014
    #2
  3. philSweet
    Joined: May 2008
    Posts: 2,691
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    After motor is broken in, you need to check the timing. I don't know about the new ones, but the old ones were shipped with any old timing, usually delayed a few degrees, probably to stop people from grenading them in the first ten hours.
     
    philSweet, Sep 15, 2014
    #3
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