75/90/115/115 Pro XS/125 OptiMax - Mercury

GENERAL INFORMATIONPropeller SelectionThe propeller on your outboard is one of the most importantcomponents in the propulsion system. An improper propellerchoice can significantly affect the performance of your boat andcould result in damage to the outboard engine.When choosing a propeller, a full selection of aluminum andstainless steel propellers specifically designed for your outboardare available through Mercury Marine. To view the entire productoffering and find the correct propeller that is best suited for yourapplication, visit www.mercmarinepropellers.com or see yourlocal authorized Mercury dealer.SELECTING THE CORRECT PROPELLERAn accurate tachometer for measuring engine speed is importantin choosing the correct propeller.Choose a propeller for your boating application that will allow theengine to operate within the specified full throttle operatingrange. When operating the boat at full throttle under normal loadconditions, the engine RPM should be in the upper half of therecommended full throttle RPM range. Refer to Specifications.If engine RPM is above that range, select a propeller ofincreased pitch in order to reduce engine RPM. If engine RPM isbelow the recommended range, select a propeller of reducedpitch to increase engine RPM.IMPORTANT: To ensure proper fit, and performance, MercuryMarine recommends the use of Mercury or Quicksilver brandedpropellers and mounting hardware.eng 29