1GM RPM
Your 1GM is rated 7.5 HP at 3600 RPM. A good continuous speed would be 80% of that or the 2800 that you now turn. Turning faster and going faster do not always happen together. The greater the boat speed the more HP is required. Once you have reached the "hull speed" of your boat, it takes a whole bunch more HP to go just a little bit faster. Plot a curve of boat speed vs RPM. You will see a virtually straight line until you get close to hull speed. When the line bends, you are at your most efficient speed. To alter that you may have to change props, clean the bottom or make some other change.
