Re: 1989 110 HP Johnson
The pitch is the theoretical distance a prop moves forward in one revolution - assuming there is no "slippage" between the prop blade and the water.
Your WOT (wide open throttle) RPM should be about 5600-6000. What is it currently, and what is the size of the current prop? Run the boat at WOT under normal operating load to determine the maximum RPM you are able to obtain. If your test results in your being able to over-rev the engine(in which case, slow down, do not continue), you need to increase the pitch of the prop. Increasing the pitch by 1" will result in approx a 200 RPM drop. If you are lugging, you would need to decrease pitch. Decreasing pitch would increase your RPM.
When your WOT RPM falls within the 5600 to 6000RPM, you have a prop that is suited correctly for your boat with respect to RPM.
