Prop suggestions for 18HP Nissan 2 stroke

Discussion in 'Prop Shop' started by jwarren, Mar 31, 2014.

  1. jwarren

    jwarren I Love microskiff.com!

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    Just tried out a new Solas in 9.25x8 yesterday; standard prop is 9.25x9. I went lower to gain better holeshot and to help when I raised motor higher. Boat runs great....except, my revs are too high.
    On second hole/trim position, I averaged 22 mph at 5900 rpms and on third hole/trim position, I averaged 22.8 at 6150 rpms. Both of these rpms are outside of 5300-5800 specs. I didn't cavitate or porpoise so I'm thinking homemade JP can go 1.5" higher. Will that make rpms even higher? Thoughts?
     
  2. your prop is slipping on the third trim setting thats why your rpms are way up, to go from 5900 at 22 and get 250 more rpm out of it but only gain .8 mph means your trimmed to high. small motors on heavy boats like your stumpknocker need to rev as high as they can within the limits so i dont think you will get a better setup. only way your going to get better holeshot is if you out a 25hp on it a 18 hp nissan is really only a 15 hp
     

  3. jwarren

    jwarren I Love microskiff.com!

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    Thanks for the feedback. I'm OK with the speed...just concerned with RPMs. Does my hydrofoil have any effect on rpms? I'm trying to get as skinny as possible and feel like I can raise another 1-1.5" but will that only increase RPMs further?

    If so, then I guess I'd go back to the OEM 9 pitch.
     
  4. jwarren

    jwarren I Love microskiff.com!

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    I recently raised motor another 1.5" higher on jack plate and am getting about the same RPM's and pick up another .3-.5 mph. No cavitation at all...plate is about 1.5" above hull line. Will I burn my motor out running WOT at 5900-6000 RPMS during short runs of 5-10 minutes? That's about the longest I'd run b/c the river depth won't let you run too long before you come upon a shoal.

    Also, what effect if I remove SE Sport200 hydrofoil? And, will adding Bennett self levering trim tabs help with raising stern at slow speeds?