Express Mach4 Propeller 13.25x17 – 4-Blade Stainless Steel, RH Rotation | 40–150hp (4.25" Gearcase)

Express Mach4 Propeller — 13.25 x 17, 4-Blade Stainless Steel, Right-Hand Rotation

The Express Mach4 is a premium 4-blade stainless steel propeller built on a Swept Cleaver design — delivering the hole shot, handling, and load-carrying advantages of a 4-blade without the top-end speed penalty that typically comes with it. Built from proprietary TP17™ stainless steel with tuned exhaust vents and race-proven geometry, it’s engineered for outboards and sterndrives from 40 to 150hp with 4.25-inch gearcases.

Best Use Case

The Mach4 in 13.25 x 17 pitch is ideal for watersports boats, sterndrive applications, tri-toons, and bay boats running 40–150hp engines with 4.25" gearcases where acceleration, cornering, and load-carrying matter as much as top-end speed. The 17-pitch is a mid-to-high pitch option for this gearcase family — well-suited to lighter hulls where the engine reaches its recommended RPM range easily at wide-open throttle with a moderate load. It’s an excellent upgrade over older OEM stainless designs and will outperform most 5-blade ski props in real-world conditions. The tuned exhaust vents also deliver best-in-class reversibility, making it a strong performer in tight docking situations.

Swept Cleaver Design — How It Works

The Mach4 uses a Swept Cleaver blade profile — a 4-blade design that delivers unprecedented hole shot, lift, and rough-water stability without the top-end speed loss typical of other 4-blade props. The swept blade geometry reduces drag at high speed while the 4-blade configuration provides more constant thrust and better stern lift than a 3-blade at the same pitch.

Key Features

• 4-Blade Swept Cleaver Design — 4-blade handling, load capacity, and rough-water stability with 3-blade top-end speed.
• TP17™ Proprietary Stainless Steel — 20% higher chromium content than standard stainless for superior corrosion resistance and a higher-gloss finish. Nearly 250% stronger and 5x more durable than conventional stainless steel alloys.
• Full Hull Lift — Raises the entire hull higher out of the water, reducing wetted surface and maintaining top speed under heavy loads where a 3-blade can lose up to 3 mph.
• Tuned Exhaust Vents — Optimized for improved hole shot and best-in-class reversibility.
• Rough Water Stability — The 4-blade configuration smooths out chop and reduces porpoising, giving the helm a more planted feel at speed.
• Broad Engine Compatibility — Fits Evinrude, Honda, Johnson, Mariner, Mercury, MerCruiser, Nissan, OMC, Parsun, Suzuki, Tohatsu, and Yamaha outboards and sterndrives.

Specifications

• Part Number: 31431730
• Diameter x Pitch: 13.25" x 17"
• Blades: 4
• Material: TP17™ Stainless Steel
• Rotation: Right-Hand (Standard)
• Gearcase: 4.25" (mid-large)
• Compatible Engine Range: 40–150hp outboards & sterndrives
• Hub System: 500-Series hub kit required (sold separately)

Parts Desk Insights

Hub kit required — not included. This propeller uses the 500-Series interchangeable hub system. Confirm your engine make, model, and year against the application chart to select the correct kit before ordering. See the MasterGuard Kit 500 — 500 Series.

4.25" gearcase — verify your engine. This is the mid-large gearcase Mach4, designed for 40–150hp engines. It is a different gearcase family from the large 4.75" gearcase Mach4s designed for 90–300+hp engines. Confirm your gearcase size before ordering.

The 17-pitch is a mid-to-high pitch option for this gearcase family. If your engine is struggling to reach its recommended RPM range, step down to a 15-pitch for more bite. Browse the Mach4 lineup for this gearcase:

• Express Mach4 13.5 x 15 — 4-Blade SS, RH (4.25" Gearcase)
• Express Mach4 13 x 19 — 4-Blade SS, RH (4.25" Gearcase)

Prefer a 3-blade at this pitch? See the Express Mach3 13.25 x 17 — 3-Blade SS, RH. For the larger 4.75" gearcase Mach4 at a similar pitch, see the Express Mach4 14.5 x 17 — 4-Blade SS, RH.