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

GENERAL INFORMATIONDetermining the correct pitch size ‐ First, check the full throttleRPM under normal load condition. If the full throttle RPM iswithin the recommended range, select a replacement or upgradepropeller with the same pitch as the current propeller.• Adding 1 inch of pitch will reduce the full throttle RPM by150 to 200• Subtracting 1 inch of pitch will increase full throttle RPM by150 to 200• Upgrading from a 3‐blade propeller to a 4‐blade propellerwill generally decrease full throttle RPM by 50 to 100IMPORTANT: Avoid damage to the engine. Never use apropeller which allows the engine to exceed the recommendedfull throttle RPM range when under normal full throttle operation.PROPELLER MATERIALMost propellers manufactured by Mercury Marine are made fromeither aluminum or stainless steel. Aluminum is suitable forgeneral purpose use and is standard equipment on many newboats. Stainless steel is over five times more durable thanaluminum and typically provides performance gains inacceleration and top end speed due to design efficiencies.Stainless steel propellers also come in a larger variety of sizesand styles that allow you to dial in the ultimate performance foryour boat.3 BLADE VS. 4 BLADEAvailable in many sizes of both aluminum and stainless, 3 and4‐blade propellers have unique performance characteristics. Ingeneral, 3‐blade propellers offer good all around performanceand higher top speed than 4‐blade propellers. However, 4‐bladepropellers are usually faster to plane and more efficient atcruising speeds, but lack the top end speed of a 3‐bladepropeller.eng 31