MERCURY 48-78120-A40-19 Prop Propeller Right Spline Prop/propeller 1/4

( Manufacturer Part Number: 48-78120-A40-19 ), ( Part Type: Aluminum Prop Propeller ), ( Warranty: 30 Day )

Review MERCURY 48 Prop/propeller 1/4 Aluminum Right Hand Spline fits A40 2013–2019

The **Mercury 48" 78120 A40 19" Propeller (13 " Pitch, Right-Hand Rotation, 15 Spline)** is a high-performance, precision-engineered propeller designed specifically for Mercury outboard motors, offering an optimal balance of efficiency, durability, and thrust for both recreational and competitive boating applications. Crafted from high-grade aluminum alloy, this propeller features a robust **19-inch diameter** with a **13 -inch pitch**, delivering a powerful yet smooth thrust curve ideal for mid-range to high-speed operation. The **right-hand rotation** ensures seamless integration with Mercury s outboard drive systems, maximizing power transfer while minimizing vibration and wear. With a **15-spline shaft connection**, this propeller is engineered for secure, vibration-dampening performance, reducing fatigue and extending both the propeller s and motor s lifespan. The **A40 blade design** incorporates aerodynamic contours and optimized cupping, enhancing hydrodynamic efficiency and reducing cavitation critical for maintaining top-end speed and fuel economy. Whether used on a sportfishing boat, a high-performance cruiser, or a racing vessel, this propeller excels in delivering consistent, reliable performance across varying load conditions, from light planing to heavy acceleration. Its durable construction and precision machining make it a dependable choice for anglers, racers, and enthusiasts seeking a blend of power and efficiency without compromising on longevity.

### **Pros and Cons of buying a Mercury 48 78120 A40 19 Prop/Propeller (13 " Right, 15 Spline)**

1. **Proven Performance** The Mercury 48 78120 A40 19 is a well-established propeller design optimized for outboard motors in the 40 60 HP range. It is known for delivering strong thrust and efficiency, making it suitable for boats in the 16 20 ft range depending on weight and load.

2. **Durability and Reliability** Mercury propellers are built with high-quality materials and precision manufacturing, ensuring longevity if properly maintained. The 15-spline shaft connection is standard for many outboards, making it easy to install and replace.

3. **Versatility** The 13 " diameter and 19-inch pitch make it a good all-around propeller for cruising, light fishing, and general boating. It balances speed and power well for its intended applications.

4. **Compatibility** This propeller fits a wide range of Mercury outboards (40 60 HP range) and is a common replacement part, meaning spare parts and replacements are widely available.

5. **Fuel Efficiency** A well-matched propeller can improve fuel economy by reducing drag and optimizing engine performance, especially in cruising conditions.

6. **Resale Value** Since Mercury propellers are widely used, a well-maintained one retains value and can be resold or traded in easily.

7. **Easy to Find** Due to its popularity, you can often find this propeller at marine supply stores, online marketplaces, or directly from Mercury dealers without much difficulty.

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1. **Potential for Wear Over Time** Like all propellers, this one will experience wear from saltwater corrosion, debris, and usage. If not regularly cleaned and inspected, it may develop pitting or blade damage, reducing efficiency.

2. **Limited for Heavy Loads** While suitable for most light-to-moderate boats, it may struggle with heavily loaded or large boats (e.g., 20 ft with heavy passengers or equipment). In such cases, a larger or more aggressive propeller may be needed.

3. **Cost of Replacement** While not extremely expensive, propellers are not cheap. A new Mercury 48 78120 A40 19 typically costs between **$150 $300**, depending on whether it s new or used. Damaged propellers may require professional repair, adding to costs.

4. **Installation Challenges** If you re not experienced with propeller installation, improper alignment or torque on the spline can damage the propeller or outboard. Some users may need to take their boat to a mechanic for safe installation.

5. **Saltwater Corrosion Risk** If stored improperly or not cleaned after saltwater use, the propeller can corrode quickly, leading to reduced performance or failure. Regular cleaning and anti-corrosion treatments are necessary.

6. **Not Ideal for High-Speed Racing** This propeller is designed for cruising and general use, not for high-speed racing or extreme performance. For racing, a more aggressive pitch or diameter would be better.

7. **Potential for Damage from Debris** Propellers are vulnerable to damage from rocks, docks, or floating debris. A strike can bend blades or crack the hub, requiring replacement.

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### **Conclusion and Recommendation**

The **Mercury 48 78120 A40 19 propeller** is a solid, reliable choice for **light-to-moderate-sized boats (16 20 ft) powered by 40 60 HP Mercury outboards**, particularly for cruising, fishing, or general recreational use. Its balanced performance, durability, and widespread availability make it a practical option for most owners.

- **Buy it if:** You have a compatible Mercury outboard, your boat is within the recommended weight range, and you plan to use it for standard boating activities. It s a cost-effective way to maintain or upgrade your propeller without sacrificing performance.

- **Consider alternatives if:** Your boat is heavily loaded, you frequently tow trailers, or you need higher speeds. In such cases, a **larger diameter (e.g., 14" or 15") or a more aggressive pitch (e.g., 20" or 21")** may be better.

- **Maintenance is key:** Regularly inspect for corrosion, clean after saltwater use, and store properly to extend its lifespan.

- **New vs. Used:** If buying used, ensure there are no visible cracks, bent blades, or excessive pitting. A new propeller is worth the slight premium for peace of mind.

**Final Verdict:** For the right boat and application, this propeller is a **good, dependable purchase** that offers a strong balance of performance and value. However, always match it to your specific boat s weight, load, and intended use for optimal results.

Details:

Preowned aluminum Mercury prop/propeller 13 1/4 X 19 15 spline right hand rotation Some signs of where and chips in the edge blades see photos for more details P0109.

part #: 4878120a4019 prices

• $60.00-$125.00

specifications propboapar:

• for makes: Mercury
• for years: 2013-2019
• mpn: 48-78120-a40-19
• part type: Aluminum Prop Propeller
• warranty: 30 Day

shipping propboapar:

• cost: $24.18
• class: Economy
• type: Calculated
• carrier: UPS
• transit: 4-11 Days
• service: UPS Ground Saver

general propboapar:

• Parts Accessories > Boat Parts > Propellers
• condition: Used

seller propboapar:

• rating: 100.0%
• city: Spanish Fort, Alabama
• # reviews: 96

offer propboapar:

• started: April 13, 2026
• sold: 0
• options: Ship-to-home
• quantity: 1
• best offers: True
• availability: In Stock

payments propboapar:

• other
• wallet: Apple-pay
• credit card: Diners-club

returns propboapar:

• time: 30 Days
• paid by: Buyer
• policy: Returns Accepted

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