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Thread: Performance Improvements possible with newer 4 stroke outboards

  1. #51
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    Quote Originally Posted by slowJEEP View Post
    Merc 60 4S is just a smidge over 60ci though. 60.8 ish. Even though it's a turd in factory form, there are a few of us working to hop them up. Perhaps a 61 inch max would be better...
    You can see why it went nowhere in the usa when a 45ci sst45 craps all over it

  2. #52
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    Yep. Takes an expensive 4 stroke to out hp/ci a 2 stroke and the 60 merc is a far cry from high performance.

  3. #53
    Team Member Bateman's Avatar
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    I like mixing gas and hauling azz myself. I get tickled at my friends who think four strokes are more reliable.

  4. #54
    Team Member Flx's Avatar
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    Hi,

    I am the guy with the boosted honda 50hp

    Yes the camshaft made a hudge difference in the high rpm, i now keep getting the rev limiter at 6600rpm with 4 blade cleaver 10.5x18,

    The engine is tweaked on the ignition by at least 3 degree of advance. This also make a hudge difference, let just say it is not a quiet honda anymore. Once you twist the gas, there just no lag, it will spin to the top.

    Ive since bought a brand new boat, my next bet is a yamaha 70hp, these engine with a simple ecm reflash can gain 15hp, it would be even more with porting, camshaft and more compression.

    The major problem i had with the honda is oil ingestion by the pcv tube at high rpm. It could be easy fixed with a catch can.

    If you balance the engine i think it could run easy over 8k rpm. With headwork also !

    Lundin marine can reflash any 4stroke and is located in norway. He is a king pin.
    JBmecanical is located in australia. That guy live tune outboard.
    Thanks hydrospeed77 thanked for this post

  5. #55
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    Quote Originally Posted by Flx View Post
    Hi,

    I am the guy with the boosted honda 50hp

    Yes the camshaft made a hudge difference in the high rpm, i now keep getting the rev limiter at 6600rpm with 4 blade cleaver 10.5x18,

    The engine is tweaked on the ignition by at least 3 degree of advance. This also make a hudge difference, let just say it is not a quiet honda anymore. Once you twist the gas, there just no lag, it will spin to the top.

    Ive since bought a brand new boat, my next bet is a yamaha 70hp, these engine with a simple ecm reflash can gain 15hp, it would be even more with porting, camshaft and more compression.

    The major problem i had with the honda is oil ingestion by the pcv tube at high rpm. It could be easy fixed with a catch can.

    If you balance the engine i think it could run easy over 8k rpm. With headwork also !

    Lundin marine can reflash any 4stroke and is located in norway. He is a king pin.
    JBmecanical is located in australia. That guy live tune outboard.


    The Yamaha 70 is the same powerhead at the Mercury 50-60hp Yamaha added their own touch.

  6. #56
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    Where are you out of Flx?

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    Team Member Flx's Avatar
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    I am located in canada quebec, excuse my poor english !
    Likes hydrospeed77 liked this post

  8. #58
    Team Member Flx's Avatar
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    Yamaha f60 and f70 are infact same engine, beside the engine head,


    The lower unit on the f60 is very interesting, with 1.85 gear ratio, a guy on facebook told me you could swap both.

    My plan is to get a f70 with the f60 lower unit, and then get the ecm reflash.Name:  IMG_20190802_143347.jpg
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    Likes hydrospeed77, slowJEEP liked this post

  9. #59
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    We raced the Mercury formula race motor for one season. It was loaned to us by Mercury Racing. It needed the gears from the two stroke motor. Other than that it was great.Name:  FB_IMG_1534081163596.jpg
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  10. #60
    Team Member Flx's Avatar
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    What gear ratio did you use ?

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