Heads Johnson 115.

[Balder]

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

[SS Minnow]

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

[racer]

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.