Express® Mach4 15.3x13 – 4-Blade Stainless Steel Propeller | 90–300+hp (4.75" Gearcase)

Express® Mach4 15.3x13 – 4-Blade Stainless Steel Propeller

The Express® Mach4 15.3x13 is a large-diameter, high-performance 4-blade stainless steel propeller engineered for 90–300+hp outboards and sterndrives with 4.75" gearcases. Its oversized 15.3" diameter delivers exceptional stern lift, fast hole shot, and strong load-carrying capability — making it an ideal choice for heavy-duty applications including large pontoons, tri-toons, bay boats, and high-horsepower sterndrive vessels.

Built with proprietary TP17™ stainless steel and precision-balanced using the MaxSpeed™ dyno balance process, this prop delivers consistent, vibration-free performance at high RPM. Requires a 500 or 700-series hub installation kit (sold separately). Always verify your specific engine make, model, and year against the application chart before ordering.

Key Features

• Large-Diameter 4-Blade Design: The 15.3" diameter provides greater blade area for superior stern lift, improved load handling, and strong hole shot — particularly effective on heavy hulls and high-horsepower applications.
• Proprietary TP17™ Stainless Steel: Features 20% higher chromium content for superior corrosion resistance, a high-gloss finish, and exceptional strength and durability in demanding marine environments.
• MaxSpeed™ Dyno Balance: Each propeller is precision-balanced using a dyno process to ensure smooth, vibration-free operation at all RPM ranges.
• Performance-Tuned Blade Geometry: Optimized pitch, rake angles, and exhaust vents improve all-around performance, hole shot, and reversibility.
• Race-Proven Finish: State-of-the-art casting technology and race-proven finishing practices deliver tight tolerances and consistent blade-to-blade balance.

Specifications

• Diameter x Pitch: 15.3" x 13"
• Blades: 4
• Material: TP17™ Stainless Steel
• Rotation: Right-Hand (Standard)
• Gearcase: 4.75"
• Engine Range: 90–300+hp
• Hub System: 500 or 700-Series (hub kit required, sold separately)

Left-Hand Rotation Option

• Express® Mach4 15.3x13 – 4-Blade Stainless Steel Propeller (LH Rotation)

Other Pitch Options – Express® Mach4 (4.75" Gearcase)

• Express® Mach4 15x15 – 4-Blade Stainless Steel, RH Rotation
• Express® Mach4 14.5x17 – 4-Blade Stainless Steel, RH Rotation
• Express® Mach4 14x19 – 4-Blade Stainless Steel, RH Rotation

3-Blade Options – Express® Mach3 (4.75" Gearcase)

• Express® Mach3 14.25x17 – 3-Blade Stainless Steel, RH Rotation
• Express® Mach3 14.25x19 – 3-Blade Stainless Steel, RH Rotation

Parts Desk Insights

Best Use Case: The Express® Mach4 15.3x13 is the right recommendation for high-horsepower applications (90–300+hp) on 4.75" gearcase engines where the customer needs maximum stern lift and load-carrying performance — particularly large pontoons, tri-toons, and heavy bay boats that run with full passenger and gear loads. The oversized 15.3" diameter moves more water per revolution than a standard 14–15" prop, which translates to stronger lift and better speed retention under load. The 13" pitch is on the lower end for this gearcase, making it well-suited for heavier hulls where the engine needs help reaching WOT RPM. If the customer’s engine is over-revving at WOT, step up to the 15x15 or higher pitch options.

Counter-Rotation Applications: For twin-engine setups requiring a left-hand rotation prop, see the Express® Mach4 15.3x13 LH.

3-Blade vs. 4-Blade: The 4-blade Mach4 is the preferred choice for heavy-load applications, watersports, and rough-water conditions. If the customer is running a lighter hull and prioritizes pure top-end speed, the Express® Mach3 3-blade line may be a better fit.

Hub Kit Required: This propeller uses the 500 or 700-series hub system. Always confirm the customer’s engine make, model, and year against the application chart before recommending a specific kit number. Hub kits are sold separately and are not included with this propeller.