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  1. #1
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    Heads Johnson 115.

    Hello, i am new here and hope someone can answer my question...i have a 1998 115 Johnson Oceanrunner, this engine is fully rebuild.
    We have 95octan pumpgas here and my question is how mutch i can cut the heads, i want a bit more compression/torque.
    I have build my own raceengines for 20years but never did porting or other tunup on outboard engines so if someone can answer i hope i not need to calculate the chamber volum/compression ratio.
    Sorry about my poor english

  2. #2
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    If you do not know your current compression psi, you are just guessing.
    If you do not get a response from anyone here, what I would do is test for compression, then remove heads and bring them to machinist to cc them. Just my .02

  3. #3
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    Due to the dome in the piston you cant just cut them you need to recut the squish as well. Also depends on what it is pushing.

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