Re: Compression ratio
Compression ratio is irrelevant, Firestone. I think what you want is the psi you can measure from compression testing. Even that is misleading.
What is important in your engine is the match of compression between the cylinders. You should measure psi that match closer than 10-15%.
Because of the many variables the actual psi you measure could be anywhere from 60psi to 150psi, but it is the comparison between cylinders that is important.
Check the Top Secret file at the top of the Johnson-Evinrude Forum for instructions on measuring compression.
Good Luck.
