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Sport Series
Alpha 4®

Built Better. Proven Best.

An optimized performer made from Mercury-patented alloy.

  • Available pitches 16, 18, 20
  • Rotation LH, RH
  • Performance vent system (PVS) No
  • Boat types Aluminum, Bowrider, Commercial, Cruiser, Deckboat, Fish-n-ski, Runabout - cuddy, Runabout - open bow, Ski
  • Number of blades 4
  • Material Mercalloy
  • Fits Alpha drive, Bravo One drives, Outboards 135hp and above
  • Recommended for Inline 4, V-6, or V-8 gas sterndrives
Flo-Torq® II: Hidden Protection

Flo-Torq® II: Hidden Protection

Mercury's Flo-Torq propeller hub might just be the most important part you never see. Not only does it flex during shift changes, reducing noise and vibration. If your prop hits an underwater object, it sacrifices itself to save your lower unit. Just pop in a new hub and you're back on the water, no service call needed. The Flo-Torq hub also makes Mercury propellers compatible with most engines on the market while also providing unmatched corrosion protection.

A Higher Grade of Performance

A Higher Grade of Performance

Mercury transforms aluminum and stainless steel into the highest-quality, best-performing, most-durable marine propellers in the world. Also the best-selling, no surprise. Our experience, expertise, and proprietary technologies – Flo Torq®, Mercalloy®, X7® alloy, and PVS® (Performance Vent System) – give you a true competitive advantage. For best overall boat performance, there's no substitute for a Mercury Propeller.

Mercalloy®: Patented Performance

Mercalloy®: Patented Performance

We couldn't find an aluminum alloy good enough for our propellers. So we invented one: Mercalloy Aluminum. So unique it’s patented, Mercalloy makes for higher-strength castings. Which allows for thinner blades that create less drag. Result? Optimal performance, optimal durability, better boating.

Built with pride in Fond du Lac, Wisconsin. Trusted everywhere.

Built with pride in Fond du Lac, Wisconsin. Trusted everywhere.

How do you make a Mercury® propeller? One exacting step at a time. It starts with a prop mold. Cast in specially engineered hot wax using a 5,000-year-old technique. Reinforced with two ceramic finishes in an application process that takes two full days. Steam-heated in an autoclave at 325 degrees Fahrenheit and 100 PSI of pressure. And finally placed in a burnout furnace at more than 2000 degrees Fahrenheit – a heat that requires employees to wear aluminized protective clothing. Strengthened and shock-proofed, the mold is ready. Liquid stainless steel now fills the cavity, heated to 3000 degrees and dispensed in 50-pound dollops. Five hundred pounds of the molten metal pass through, creating 24 Mercury propellers. The freshly cast props cool on carts for about an hour. Then jackhammer-like knockout machines, abrasive saws, and sandblasters remove all traces of residual ceramic and oxidation. Machinists hone and prepare props for specific applications. And grinders thin leading blade edges and sand other areas. Next step: surface refinement. Two hours in a drag finish machine smoothes peaks and valleys, creating the matte finish of a Bravo Three® or pod-drive prop. Other propellers move on to a burnishing stage, gaining a high-luster finish. Fitting props with Performance Vent System plugs is the final step. They are now ready to be customized for better hole shot – and to deliver the superior performance Mercury owners around the world count on.


Buy the Books
Buy the Books

You can order all available Mercury literature online or through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

  • Operation, Maintenance, and Warranty Manuals
  • Parts Manual
  • Service Manual

Purchase a Manual

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