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  1. #1
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    Performance increase with flash?

    I run a Merc...I know, I know, please don't stone me to death. Figured I would ask here because you guys are more familiar with flashed out boards and the gains associated.

    There is a tune available for the new Merc 4stroke. I have a 250 on a PHX 21. How much of a gain could I expect in performance with a 300hp tune with stock rev limiter @ 6200rpm?

  2. aka Strokedyamaha StrokerSmoker's Avatar
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    #2
    just a guess but from testing mods from the dyno to the boat 10 hp increase on the dyno gets about 1 mph on the water give or take......

    Hi performance parts or a Yamaha power head visit
    Hydro-Tec's web site @ http://www.yamaha-rebuild.com/
    Paul Hottman Hydro-Tec's Pro staff since 1998

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    #3
    Since the Pro XS is using the same 4.6L from 200HP through 300HP and the max HP from a 300 within the 10% allowable overage, assuming the 300 can produce 300hp +10%.

    Max flash HP increase using the 300hp fuel mappings should push a 200hp-250hp up into the 330hp range.

    So for your 250hp it would have the potential to increase HP 60-80hp, or using the 1mph per 10hp, an increase in 6-8mph.

  4. Member Yatesville Junkie's Avatar
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    #4
    Just had my ZX 250 flashed. I will get it on the water next week and I will report back. Before the flash solo I was running 73-74 and loaded I was seeing 70-72. Stock 25 T1 prop. Had the limiter raised to 7000 RPM. Im expecting 5-8 MPH.
    2020 Ranger Z520L 250 Pro XS 4

  5. Member
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    #5
    Quote Originally Posted by Yatesville Junkie View Post
    Just had my ZX 250 flashed. I will get it on the water next week and I will report back. Before the flash solo I was running 73-74 and loaded I was seeing 70-72. Stock 25 T1 prop. Had the limiter raised to 7000 RPM. Im expecting 5-8 MPH.
    It’ll be more like 3-5 mph increase.

  6. Member Yatesville Junkie's Avatar
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    #6
    I’ll take it.
    2020 Ranger Z520L 250 Pro XS 4

  7. #7
    I got about 2-3 mph increase by simply flashing to the 300 HP. I did not raise the limiter on mine.

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    #8
    2-3 mph is what I got from my 2015 Zx250. Of course I will not spin it past 6200 rpm.

  9. Member Yatesville Junkie's Avatar
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    #9
    I’m gonna have my prop reworked and set her up to run in the 6500 to 6800 range.
    2020 Ranger Z520L 250 Pro XS 4

  10. aka Strokedyamaha StrokerSmoker's Avatar
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    #10
    Quote Originally Posted by Yatesville Junkie View Post
    I’m gonna have my prop reworked and set her up to run in the 6500 to 6800 range.
    it will run the best at those rpms

    Hi performance parts or a Yamaha power head visit
    Hydro-Tec's web site @ http://www.yamaha-rebuild.com/
    Paul Hottman Hydro-Tec's Pro staff since 1998

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    #11
    Thanks fellas! More to gain by spinning past the factory rev limiter??

  12. Member Yatesville Junkie's Avatar
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    #12
    That’s the way I understand it but I could be wrong.
    2020 Ranger Z520L 250 Pro XS 4

  13. Member
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    #13
    I know that there is a flat spot around 6000rpm and getting those rpm's up really wakes it up but I'm gun shy with cranking out the rpm more then 6200ish. Cracked heads last year on my 2014 SHO and unsure what happened but I am not going to tempt fate!

  14. Member Yatesville Junkie's Avatar
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    #14
    I honestly will probably never push it to the max all the time. I wanted it for the add midrange and hole shot. But if I want to go fast I can too. I’ve been told the SHOs are like Diesel engines and are restricted a lot. I’ve had two diesel trucks and no issues hopefully the same holds true. I trust the Hyro Tec boys and if she blows that’s who I will have fix it.
    2020 Ranger Z520L 250 Pro XS 4

  15. #15
    Are SHO motors even rebuildable???

  16. Member
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    #16
    Quote Originally Posted by bassmasterffej View Post
    Are SHO motors even rebuildable???
    I have heard no and yes. Verdict seams unsure

  17. aka Strokedyamaha StrokerSmoker's Avatar
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    #17
    Quote Originally Posted by bassmasterffej View Post
    Are SHO motors even rebuildable???
    Yes Hydro tec has done several the block is composite with sleeves if the block is damaged no way to really repair....everything else is rebuild-able crank rods pistons heads
    and you may even be able to replace sleeves they are similar to the nickel plated merc 280s

    Hi performance parts or a Yamaha power head visit
    Hydro-Tec's web site @ http://www.yamaha-rebuild.com/
    Paul Hottman Hydro-Tec's Pro staff since 1998

  18. Member Yatesville Junkie's Avatar
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    #18
    Got my ECU back and put it on yesterday. Ran her loaded up solo and she ran 76.7 at 6500 Rpm with stock 25 T1. Almost a 4 mph gain from my previous best. I need to re adjust my jackplate and I think she will do better. Im at 5.5 dots and she was walking pretty bad. The time it takes to get to 70 is whats most impressive, like driving a sports car. I would highly recommend the flash to anyone looking at it. The power is defiantly noticeable. Im going have my prop reworked by Mark and do some plate adjustments. Once dialed in I will video it. Not use to driving a rig that walks but Id say its my setup.
    Last edited by Yatesville Junkie; 05-11-2019 at 05:41 PM.
    2020 Ranger Z520L 250 Pro XS 4

  19. Member
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    #19
    Raise the engine until you loose water pressure or speed, then back down till it comes back.if you loose bow lift trimmed you went too high also. That will be your best spot trimmed out. Also it reduces the tendancy to walk or hunt. When it moves to the right bump to the right and vise versa. It is just like riding a bike only bigger and alot faster! Cj
    2002 X19 200HP OX66 HO Vmax,HPDI lower, it lives, thanks Hydro Tec.

  20. Member Yatesville Junkie's Avatar
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    #20
    Test Run #2.
    I raised the plate to 7 dots and speed was 76.8 at 6550 RPMs, but was way easier to control this time. She only started walking when I over trimmed it at the end. All and all Im very happy with the flash and looks like the prop I have will be good enough for me. I am still gonna have it sent off to Mark for work and see if its any better. As for fuel burn, she will drink it if I run her hard. But at cruising speeds Im any where from 500-800 RPM less than normal so it should balance out. Again its amazing how quickly the boat will race to 70 mph now.
    2020 Ranger Z520L 250 Pro XS 4

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