Mercury Black Max 9.5x11P Aluminum Propeller (25-30 HP)

The Mercury Black Max 9.5x11P is a high-performance aluminum propeller with increased pitch, compatible with Mercury/Mariner 25-30 HP outboards. Part of Mercury’s renowned Black Max lineup, this propeller is tailored for boaters looking to maximize top-end speed under the right conditions. If your boat is relatively light or your engine easily hits the rev limiter with a lower-pitch prop, switching to this 11″ pitch prop can boost your top speed while still maintaining solid acceleration and dependable handling.

With a 9.5-inch diameter and 11-inch pitch, this 3-blade prop is designed to let your engine run at slightly lower RPM at wide-open throttle compared to the 9.5P version. The higher pitch means the propeller moves farther through the water with each rotation, translating into greater speed potential at a given engine RPM. This makes the 9.5x11P ideal when a standard lower-pitch prop was allowing the engine to over-rev; the 11" pitch will keep the engine in its optimal RPM range at WOT, improving fuel economy and reducing strain. At the same time, the 9.5″ diameter and carefully engineered blade profile ensure that acceleration remains smooth and the boat still responds well at low speeds, so you sacrifice minimal holeshot performance when moving up to this prop.

Like all Mercury Black Max propellers, the 9.5x11P is built from a durable Mercalloy aluminum and finished with Mercury’s signature black anti-corrosion coating. This finish guards the prop against rust and damage, providing longevity even in saltwater service. Installation is plug-and-play – the prop comes with the standard 10-spline hub that fits directly onto your Mercury/Mariner’s prop shaft. No special hub kit is required, as this prop is an OEM-style replacement designed for a perfect fit. With the Mercury Black Max 9.5x11P, you can achieve higher speeds and efficient cruising on your small boat, all while retaining the trusted quality and reliability of genuine Mercury propellers.

Recommended Uses and Applications:

• Best suited for lighter boats (around 10 – 15 ft) powered by 25-30 HP outboards where the engine currently hits high RPM easily – the taller 11" pitch allows for higher top speeds on such setups
• Suitable for skiffs, jon boats, or runabouts that previously came with a 9.5" pitch prop and were over-revving – this 11P prop will load the engine correctly and improve fuel efficiency at cruise
• On minimally loaded boats (e.g., one person aboard a light craft), this prop enables faster travel and lower engine RPM at cruising speeds, resulting in a quieter, more economical ride
• Note: If your boat is on the heavier side or struggles to reach proper RPM, a lower-pitch prop (e.g., 9") is recommended for better acceleration and to ensure the engine operates in its optimal range under load