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  1. #1
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    Whats a good prop size for a 115 Johnson?

    Currently has a 13.5 x 20 Raker. It's a little crappy (not horrible) out of the hole and does okay on top end running around 5300-5500 rpms. Not looking for strictly speed but not looking to sacrifice any either to get a bit better bottom end. I'm thinking 13.5 X 19 maybe? Anybody know what a popular size/pitch is for this engine? No jackplate, just the 6" factory setback built into the transom of a 17' R70 Ranger. Normally just me and not a lot of gear in the boat.

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  3. Moderator 21XDC's Avatar
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    #2
    You might benefit most by having Mark drill pvs holes into your prop and add a little cup to the tips.

  4. Member LaveyT's Avatar
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    #3
    +1 On the PVS holes, What RPM does your motor jump to on hole shot now?

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    #4
    Quote Originally Posted by LaveyT View Post
    +1 On the PVS holes, What RPM does your motor jump to on hole shot now?
    I need to look at that closer...cant really give the numbers not having looked close at them. Got some hesitation from the hole but could need a linc/sync. I probably should do that first. There are holes in the barrell of the prop.. close to where each ear joins the barrell.

  6. Member
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    #5
    Quote Originally Posted by 21XDC View Post
    You might benefit most by having Mark drill pvs holes into your prop and add a little cup to the tips.
    pvs holes are for ventilating the prop I'm guessing?

  7. Member
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    #6
    the small Raker does have small PVS holes in the prop but they are very smallish probably around 3/8".I believe you would run better with the motor Raised up a little my 140 on my old boat ran this exact prop but i had it raised up on the Jackplate I believe 3/4" thats heavily loaded with 2 people in the boat.A 13.5 x 22 renegade will run almost identical to the Raker but will have a tad better holeshot.
    Lets Rock and Roll....

  8. Member
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    #7
    I have a 2005 Stratos 275 Pro XL that weighs 1400 lbs. I started with the same prop you mentioned ( 13.5" X 20p Raker ). Same thing here, hole shot was not good, not horrible either. Although, top end was 51 mph + at about 5750 RPM. I had Mark Croxton work an old SST 12 3/4" X 21p back into running condition and put that on the back of my 115hp Johnson. The hole shot improved to "acceptable" to decent range and top end is right at 50 mph at 5500 RPM with two people and gear. The prop is performing the way I hoped it would. It's not what could be termed a "performance prop" but with the limited hp and no jack plate, it does fine. I'm certainly not a prop expert by any means but my theory is that the smaller blades allow the prop to spin faster at take-off thereby getting the RPM's up and allowing the motor to get to a higher hp level where it can effectively move the heavy boat better. Just my 2 cents.

  9. Moderator 21XDC's Avatar
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    #8
    Quote Originally Posted by WIJoe View Post
    I'm certainly not a prop expert by any means but my theory is that the smaller blades allow the prop to spin faster at take-off thereby getting the RPM's up and allowing the motor to get to a higher hp level where it can effectively move the heavy boat better. Just my 2 cents.
    This is what PVS holes do even on larger props.... Some props have small exhaust ports... Not to be confused with "PVS" holes like some think. The pvs holes are a lot bigger and will let a prop spin up better for a better holeshot, and yet if it vents too hard, can be adjusted with $2 plastic pvs plugs to dial in the perfect rpms... Normally 3500-4000.

  10. Member cubswin's Avatar
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    #9
    my javelin 18 with a 115 I ran a renegade 21 on, liked it more than the 20 raker. Lost some top end with the raker, but everything else was better.