Guesstimating pitch on a 30hp Yammi

Discussion in 'Prop Shop' started by SWFL_Gheenoe, Dec 29, 2017.

  1. SWFL_Gheenoe

    SWFL_Gheenoe Active Member

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    Hey guys, I bought a old 30 horse yammi a few weeks back, ran nicely for my first trip on my Classic Gheenoe, but now its starting to show symptoms of a cylinder not firing. Bringing it to my local shop next week, but in the mean time - I have absolutely no idea what size prop is on this thing. Its a nice 3 blade stainless, but havent been able to find any size specs on it.
    Id like to get a spare prop for it, but also wouldnt mind making that "spare" a potential performance improvement.
    I got a tiny tach that ill install as well, but even at that, how do I decide what pitch to go with for the spare? I feel like I see the 13p talked about most often with these engines, but that could also mean next to nothing.
     
  2. Smackdaddy53

    Smackdaddy53 Zephyr Cove is on FIRE!

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    Take it to a prop shop and they can put it on a pitch jig and tell you.
     

  3. SWFL_Gheenoe

    SWFL_Gheenoe Active Member

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    Didnt even know that was a thing! Will do, thanks
     
  4. No Bait / Lures Only

    No Bait / Lures Only I Love microskiff.com!

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    I have a similar motor, 2 stroke 25 2 cylinder Modified Yamaha on a Spear Glade x. Tried 3 props on it with a tiny tac for engine speed, the perfect prop for me was the Power Tec SRA 3 x 12" pitch 5850 rpm. Tried a Solas 13" and it was tooooo much pitch and cup as it had been modified 5100 rpm. Also tried the Turbo Hot Shot 12" 6800 rpm+ too much rpm as it hit the rev limiter. Try to get a prop to keep your rpm higher in the range so when it is loaded it will be spot on. The Solas is for sale if you need a spare. Been using the Power Tec fo 4 years now with no issues....
     
  5. SWFL_Gheenoe

    SWFL_Gheenoe Active Member

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    Just need to convince myself to bite the bullet on a powertec... Ive heard very good things about the SRA3's, in both 12" and 13"
     
  6. No Bait / Lures Only

    No Bait / Lures Only I Love microskiff.com!

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    Power Tec SRA3 is the prop of choice for little light skiffs or flat boats, very happy with mine. You might be able to buy a used s/s prop on this site....list what you need, you never know until you ask.....
     
    SWFL_Gheenoe likes this.
  7. No Bait / Lures Only

    No Bait / Lures Only I Love microskiff.com!

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    Try changing the plugs as that worked with my motor was showing the same symptoms...Also try borrowing a prop as buying new is expensive just to test...
     
  8. No Bait / Lures Only

    No Bait / Lures Only I Love microskiff.com!

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    6000 rpm is a good start for the motor..