Mercury – SpitFire 4-Blade Aluminum Propeller | 14” Diameter x 21” Pitch | Right-Hand Rotation | 4 Blades | Aluminum | Polished Finish | 8M0084496

Overview

There is a certain thrill in throttling up and feeling your boat leap forward, steady and sure, like it’s reading your mind. That is the kind of connection you get with the Mercury SpitFire 4-Blade Aluminum Propeller (Part Number 8M0084496). Built for boaters who crave responsive control and quick lift, this prop grips the water with confidence and keeps you cruising smooth. From takeoff to top speed, it delivers a mix of acceleration, balance, and handling that feels effortless ,no drama, no hesitation, just clean performance that makes every trip more enjoyable.

Key Features

• Diameter and Pitch: 14” Diameter x 21” Pitch
• Rotation: Right-Hand
• Blade Count: Four blades for enhanced lift, stability, and grip
• Material: Patented Mercalloy aluminum alloy — engineered for strength and impact resistance
• Finish: Polished aluminum for sleek looks and lasting performance
• Hub System: Flo-Torq II Hub Kit (Part Number 835257K1) included for drivetrain protection
• Design Details: Aggressive blade geometry for faster acceleration and superior handling

Engine & Boat Compatibility

• Designed for Mercury and Mariner 90–115 HP FourStroke Command Thrust outboards
• Fits Mercury and Mariner 135–300 HP TwoStroke and FourStroke outboards
• Compatible with MerCruiser Alpha One and Bravo One sterndrives
• Ideal for runabouts, pontoons, and fishing boats, delivering steady lift, tight turns, and smooth cruising across varying water conditions

Performance Benefits

• Instant acceleration: The SpitFire 14x21 launches hard and fast, providing 16–25% quicker acceleration than a comparable three-blade prop. You’ll notice it right away — a firm, sure-footed grip that pulls you onto plane in seconds.
• Smooth and stable handling: The four-blade design holds the water through turns, keeping your control precise even when chop or current try to push back. At cruising speeds, it runs quiet and balanced, making every ride feel composed.
• Durable and forgiving: Built from Mercury’s Mercalloy aluminum alloy, it’s both strong and flexible, able to withstand light impact without giving up reliability. That’s real-world toughness designed for everyday boaters.
• Added protection: The Flo-Torq II Hub Kit absorbs much of the shock from minor underwater strikes, helping safeguard your engine’s drivetrain and keep you on the water longer.
• Low maintenance, high payoff: It’s easy to care for, resists corrosion, and keeps performing season after season with minimal upkeep.

Why is this prop is a strong choice vs. alternatives?

The Mercury SpitFire 4-Blade Aluminum Propeller strikes the perfect balance between performance, value, and dependability. It’s Mercury OEM quality, crafted by the same engineers who design the engines it powers — so you know every detail has been tested for real conditions, not just lab specs. It rivals the punch of a stainless prop but without the added cost, making it a smart upgrade for boaters who want serious performance on a practical budget.

Its versatility across engine sizes and boat types makes it a reliable choice whether you’re slicing through calm water or pushing through waves. With durable construction, simple maintenance, and a design that boosts acceleration and control, the SpitFire 14x21 delivers performance you can trust, trip after trip.

FAQ

Q1: Which Mercury engines does the SpitFire 4-Blade fit?

It fits Mercury and Mariner 90–115 HP FourStroke Command Thrust outboards, 135–300 HP TwoStroke and FourStroke outboards, and MerCruiser Alpha One and Bravo One sterndrives.

Q2: What makes this propeller different from other Mercury options?

The SpitFire combines the control and lift of a four-blade design with the speed and top-end performance of a three-blade prop, offering a blend of grip, acceleration, and balance.

Q3: How do I know if this pitch or size is right for my boat?

If your engine performs within its recommended RPM range using a 21” pitch prop, this model will likely be an excellent fit. Check your owner’s manual or speak with a Mercury dealer for confirmation.

Q4: Can this prop be used in both saltwater and freshwater?

Yes. The aluminum alloy and polished finish make it suitable for both environments. Rinse thoroughly after saltwater use to maintain its smooth finish and performance.

Q5: What hub system does it use?

It includes the Flo-Torq II Hub Kit (Part Number 835257K1), which cushions your drivetrain against minor impacts and helps prevent damage during unexpected contact with debris.