engine compression and rpms

[freds]

air temperature can have an effect on how your outboard engine runs.my dad says his 150hp will run 3mph faster in 50 degree temp than in 90 degree temp.i dont know a lot about the compression and rpms but you would think if you are loosing compression you could not turn the proper rpms.

[trex1]

First place to check is the prop. If it's not perfect you will lose speed. Load change will also change your set-up...