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Thread: Performance upgrades on a 25 2cyl Yamaha?

  1. #1
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    Default Performance upgrades on a 25 2cyl Yamaha?

    I have a 2005 2cyl 2 stroke yamaha that’s about to be put on a 542 War Eagle. Looking to get a little more Zip out of the 25. Anybody ever messed with a similar motor or know how to point me in the right direction as far as what Carbs/reeds/prop to run? Open to any suggestions. Thanks

  2. #2
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    I've got the Chris Carson reeds in mine. Mine idles better now. Supposed to get better holeshot and fuel economy but I can't tell.

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  3. #3
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    Try the boats & blinds forum. This topic has been discussed before. Not much you can do with a 25, 2 cyl.

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  4. #4
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    Add a cylinder...

  5. #5
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    Quote Originally Posted by FishSticker View Post
    Add a cylinder...
    This.

  6. #6
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    Thanks, i’m trying to buy a 3cyl as we speak but was just wondering if I could get some more Zip out of mine before I bought another. Looking for a DT 25 Suzuki or a 25 yamaha 3 cyl if y’all know anybody who has one. Preferably stock.

  7. #7
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    Don’t waste your money trying to build it up. Go ahead and find a 3cyl or look at a tohatsu 4 stroke.
    Sea Ark 1542 w/ Yamaha 40
    Xpress 16 w/ 50 Hammer
    War Eagle 15 w/ 30 Hammer

    --------------------------------------------------

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  8. #8
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    Had to rebuild my 25. During the process we Shaved the head and put aftermarket reeds. No top end difference.



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  9. #9
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    Take advice from someone who went to the end of that rabbit hole and back. Keep your 2 cyl stock and enjoy your 30mph boat. If you wanna go faster buy a 40. The foot is the weak link of those 3cyl 25's. They cant tote bumping stumps like an ol 25 merc or 2cyl yammy. You will spend hundreds of dollars to gain 5mph and have a motor that is finicky as shit. They are heavy to pick up over logs, and gotta get a hard to find flywheel to make them estart. I almost unbolted mine in the cache river one morning and let it sink. When it ran good it ran like a raped ape but when it didn't I cussed it. I can name several on here that rode in mine or watched mine run and had to have one. They chased that rabbit and later sold it in favor of a 40. Keep that 2cyl for the meto and buy you a big boat with a 40+ for the river.
    "Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of the rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs.
    I am haunted by waters" Norman Maclean.

  10. #10
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    Quote Originally Posted by Phone Man View Post
    Take advice from someone who went to the end of that rabbit hole and back. Keep your 2 cyl stock and enjoy your 30mph boat. If you wanna go faster buy a 40. The foot is the weak link of those 3cyl 25's. They cant tote bumping stumps like an ol 25 merc or 2cyl yammy. You will spend hundreds of dollars to gain 5mph and have a motor that is finicky as shit. They are heavy to pick up over logs, and gotta get a hard to find flywheel to make them estart. I almost unbolted mine in the cache river one morning and let it sink. When it ran good it ran like a raped ape but when it didn't I cussed it. I can name several on here that rode in mine or watched mine run and had to have one. They chased that rabbit and later sold it in favor of a 40. Keep that 2cyl for the meto and buy you a big boat with a 40+ for the river.
    +1. This is good advice

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  11. #11
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    I have not read anyone tell him to "hook" the boat or post pics of themselves sitting in the bottom.

  12. #12
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    Quote Originally Posted by Highstrung View Post
    I have not read anyone tell him to "hook" the boat or post pics of themselves sitting in the bottom.
    "hook" was D's Tees word

  13. #13
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    Quote Originally Posted by Phone Man View Post
    Take advice from someone who went to the end of that rabbit hole and back. Keep your 2 cyl stock and enjoy your 30mph boat. If you wanna go faster buy a 40. You will spend hundreds of dollars to gain 5mph and have a motor that is finicky as shit.
    Good advice!
    \"Free your mind, your ass will follow\"

  14. #14
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    Getcha one of these to modify.

    212BA645-D194-40A1-B2BD-B0971E6E468E.jpg

  15. #15
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    Quote Originally Posted by 3 1/2" MAGUM View Post
    Getcha one of these to modify.

    212BA645-D194-40A1-B2BD-B0971E6E468E.jpg
    This guy gets it

  16. #16
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    What is that? 50hp merc?
    Miner's Daughter's Coal Train 'Rosco'

    "The only human quality he lacks is speech" -Alfred Brehm




  17. #17
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    Quote Originally Posted by Birddawg View Post
    What is that? 50hp merc?
    59 cu inch Merc....40/50/60 HP 3 cyl

  18. #18
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    Sticker is correct.

  19. #19
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    I’ve run 2 stroke Yamaha 25hp motors pretty much exclusively for the last 11-12 years. I don’t use them for the speed aspect, but the reliability.

    I wouldn’t mess with mine to gain a few miles per hour and potentially screw something up inadvertently.

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