Turning Point Express Mach4 Propeller 14x21 – 4-Blade Stainless Steel, LH Rotation

4-Blade Dual Geometry Stainless Steel Propeller – Left-Hand Rotation for Twin-Engine & Counter-Rotating Applications

The Express Mach4 14x21 Left-Hand Rotation is a 4-blade stainless steel propeller engineered for boats running 90–300+ hp engines with 4.75" gearcases. It is the counter-rotating companion to the Express Mach4 14x21 Right-Hand Rotation, designed for the port side of twin-engine installations where left-hand (counter-clockwise) rotation is required.

Like the RH version, it uses a patented Dual Geometry design — two blade profiles in a single hub — to deliver the acceleration, stern lift, and rough-water stability of a 4-blade while maintaining top-end speed on par with a comparable 3-blade prop. Two blades use an aggressive variable-rake geometry for explosive hole shot and sharp cornering; the other two use an offshore-style design for high speed and maximum stern lift.

Built from proprietary TP17™ stainless steel — 20% higher chromium content, ~250% stronger and 5× more durable than standard stainless — with large free-flowing exhaust ports (40% more exhaust area than typical competitors) to reduce backpressure and extract maximum power.

Key Features

• Left-hand (counter-clockwise) rotation — purpose-built for twin-engine and counter-rotating applications
• Dual Geometry design — two blade profiles in one hub for 4-blade handling with 3-blade top-end speed
• Unprecedented hole shot, bow lift, and rough-water stability
• Lifts the hull higher under load — maintains speed when fully loaded where a 3-blade can lose up to 3 mph
• Proprietary TP17™ stainless steel — 20% more chromium, ~250% stronger, 5× more durable than standard stainless
• Large free-flowing exhaust ports — 40% more exhaust area for reduced backpressure
• 14" diameter × 21" pitch, 4-blade configuration

Ideal Applications

The Mach4 LH excels on the port engine of twin-engine pontoon and tri-toon boats, sterndrive applications, watersports tow boats, and bay boats where counter-rotating props are used to eliminate torque steer and improve straight-line tracking.

Engine Compatibility

Fits a wide range of outboard and sterndrive applications including Cox®, Evinrude®, Honda®, Johnson®, Mariner®, Mercury®, MerCruiser®, Nissan®, OMC®, OXE®, Parsun®, Suzuki®, Tohatsu®, Volvo Penta®, and Yamaha® engines. Always verify fitment using the manufacturer’s application chart.

Required Hub Kit

A hub/installation kit is required and sold separately. Use a 500 Series Hub Kit for engines under 200 hp, or the 700 Series Hub Kit for engines 200 hp and above. Refer to the application chart for the correct part number for your engine.

Right-Hand Rotation Also Available

For the starboard engine or single-engine applications, see the Express Mach4 14x21 Right-Hand Rotation.

Parts Desk Insights

Best Use Case: This is the port-side prop for twin-engine setups running the Mach4 in a counter-rotating configuration. Customers typically buy this paired with the Mach4 14x21 RH for a matched set. The Mach4 is the right recommendation when a customer needs better hole shot, stern lift, or load-carrying performance than their current 3-blade delivers — without giving up top-end speed.

Rotation Clarification: Left-hand rotation is required on the port engine of most counter-rotating twin-engine setups. Always confirm the customer’s engine rotation requirement before ordering — this is the most common mistake on twin-engine prop sales. If unsure, ask the customer to check the existing prop rotation or consult the engine manufacturer’s spec sheet.

Pitch Selection: The 21" pitch suits mid-to-high RPM applications. Confirm WOT RPM falls within the engine manufacturer’s recommended range. Step down to the Mach4 13x19 if over-propped, or up to the Mach4 14x23 if under-propped.

Hub Kit Note: Always confirm the hub kit part number from the application chart. The MasterGuard Model 517 is a common fit for many 500 Series applications.