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  1. #1
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    Needing advise for 2006 Eagle 175 with 90 Yamaha

    I have a few questions/needing advice. I recently purchased a 2006 G3 Eagle 175 with a 2005 Yamaha 90hp 2 stroke. It currently has a Solas 13.25x17 pitch ss prop on it that was on the boat when I bought it. The motor is mounted in the second hole from the top. The first couple of trips taking the boat out, it porpoised very badly. I could only run it up to about 37 mph(gps) before it got out of hand and about 4200-4300 rpm at WOT. So I bought a SE Sport hydrofoil and it solved the porposing issue, I can now trim a little past half way on my trim gauge, and the only part of the boat in the water is a little bit behind the seat. But with solving that issue, I’m still not at the correct rpm range at WOT that I should be. Currently, the best I can get is about 4600-4700 rpm WOT and 40mph with the current setup. My dad has a xpress with a ballistic 13.375x 19p ss prop that we put on just to see the difference. With the 19p prop it took alittle longer to plane out, which was expected, and only turned 4400-4500 rpm and 39 mph(gps). I’ve done several prop/pitch calculators that include slip and every single one that I do says for my 17p prop to run 40mph I would definitely have to be turning over 5000 rpm. So that is where I am getting a little confused. Would it be worth my time to try and find a friend or someone to possibly try a 15 pitch and see what that does? Or could it be that I should try a different brand 17p prop? I’m not worried about making the boat’s top speed any higher, just want to run the motor higher up in the rpm range like it is supposed to. Any advise or tips would be helpful. Thanks in advance.
    Last edited by dstokley; 04-17-2019 at 04:28 PM.

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  3. Member tlefire's Avatar
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    Feb 2017
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    Talladega, AL
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    #2
    First thing I would check is to make sure your tack is set correctly. I run a 17 pitch on my F90, 4 stroke, WOT is 5900.

  4. Member
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    Apr 2019
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    Laurel, MS
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    #3
    Thanks. I’ll double check it. It was set to 6P I’m almost positive. I rotated the adjustment screw on the back of the tach. I read on here that could sort of clean the connection off.

  5. Member
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    Feb 2015
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    Raleigh, NC
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    #4
    I have the same motor 2006 90 2 stroke on a 2006 G3 1966 CC. my prop is a Power Tech SCD4R16PYM90
    I had some porpoise issues but moved TM batteries forward . I can see 35-37 GPS. Not a techy prop guy so I really don't know if this helps.

  6. Member
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    Apr 2019
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    Laurel, MS
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    #5
    Ok, so you are running a 16p 4 blade. What kind of RPM are you getting at WOT? I've read on here that a lot of people don't prefer the hydrofoil but I saw a big difference on my boat. You boat weighs about 150 more than mine, so my speed seems about right I think.

  7. Member
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    Feb 2015
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    Raleigh, NC
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    #6
    I think 5500. I rarely run WOT . I also have a manual JP, and foil.
    https://bobsmachine.com/product/conv...te-200-hp-max/
    https://bobsmachine.com/product/true...r-plate-90-hp/

  8. Member
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    Apr 2019
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    Laurel, MS
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    #7
    Not sure if anyone is reading up on this but may help someone down the road. I got my hands in a 13.25x15p power tech red3 ss prop and my wot rpm went to 5200-5300 and 38-39 mph gps. Originally with the 17p solas I was at 4600 rpm and 39-40 mph. I’m happy with the difference but didn’t expect to jump 600 rpm. I may try to raise my motor up one hole and try both props.

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