Scout Costa 170

Discussion in 'Prop Shop' started by texasislandboy, May 21, 2012.

  1. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    picked up a Scout Costa last week in really good shape. Has a three blade prop on it and it seems to be a good set up but its got alot of power on the top end and takes a little while to get up on plane.. WOT is around 36mph and I think around 5000 rpm. I would like to step up to a four blade and get into the 40mph range
     
  2. Brett

    Brett > PRO STAFF <

    Some useful information about top speed with 4 blades

    http://www.boattest.com/resources/view_news.aspx?newsid=3276

    http://www.savvyboater.com/3-blade-prop-vs-4-blade-prop.aspx

    http://www.marine-outboards.com/General_Info/choosing-propeller.htm
     

  3. Creek Runner

    Creek Runner Well-Known Member

    1,544
    21
    643
    It's probably not going to happen, 4 blades are slower than 3 blades. In order to swing a 4 blade wheel you will have to have less pitch which will take away from your top end.

    Rule of thumb less pitch better hole shot, more pitch more top end.

    What HP motor and model do you have?
     
  4. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    its a Yamaha 90 2 stroke 2004 with 101 hours on it motor it self runs super I think I just may have to recup my prop.
     
  5. Brett

    Brett > PRO STAFF <

    90 hp on an 800 lb hull should be doing better than 36 mph and 5000 rpm.
    Something isn't right with the setup... :-?
     
  6. Creek Runner

    Creek Runner Well-Known Member

    1,544
    21
    643
    Are you triming the motor up when running at WOT?

    Also how are getting your speed? ie GPS, Speedo?
     
  7. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    I'm going to take it out tomorrow and run it with a gps
     
  8. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    ran today and only got 30 knots out of it and it had alot more power on the top end I think I'm going to get the prop cupped and start again.
     
  9. snooks

    snooks I Love Gulp!

    55
    0
    331
    what was the rpm's at wot?.....cupping the prop will drop rpms
     
  10. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    I ran it up to 5200 and had alot more to it. gonna get it cupped this week then try again.
     
  11. Creek Runner

    Creek Runner Well-Known Member

    1,544
    21
    643
    If it had more why didn't you let it turn up? [smiley=1-mmm.gif]
     
  12. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    Didnt see the need to redline it if i knew it was 10mph slow already the stock rated boat and motor package is set to run at 47mph
     
  13. Creek Runner

    Creek Runner Well-Known Member

    1,544
    21
    643
    Texas the reason to tun it up is to get a baseline for where you are at. If the motor would have turned say 6000 well then you need a bigger prop(more pitch) which will also be the reason your not getting the speed you want.

    Cupping your prop isn't go to do anything for you.

    What size prop are you running now?

    Call Scout and ask them what is the recommened prop size they have awsome customer service.
     
  14. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    just looked at the yamaha bulletin for this boat they used a 13 1/4'' x 18 prop and the only marking on my prop is 16.... seems like its to small I'm going to order a 13 1/4'' x 18 and see what it does.
     
  15. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    http://www.yamahaoutboards.com/sites/default/files/bulletins/bulletin_2stroke_hpmidport_gyt3_sct-170costa-90tlr.pdf
     
  16. Creek Runner

    Creek Runner Well-Known Member

    1,544
    21
    643
    Is your prop SS or Aluminum? If it's SS take it to a local prop shop and tell them you want to make it an 18" it will be about 1/3 the cost of a new prop.
     
  17. texasislandboy

    texasislandboy I Love microskiff.com!

    61
    0
    81
    It is and will do! I'm going to buy a cheap aluminum prop for a spare and test it before I get them to do my prop.