1. Boat Outboard Engines To Buy
  2. sku: 23684905384509793
  3. MERCURY 43-47351

MERCURY 43-47351 Lower Unit Pinion Gear

fits make: Mercury.

43-47351 Mercury Oem Lower Unit Pinion Gear

( Manufacturer Part Number: 43-47351 ), ( Part Type: Pinion Unit Gear ), ( Country Of Origin: United States )

Review MERCURY Oem Lower Unit Pinion Gear

The **Mercury 43-47351 Lower Unit Pinion Gear** is a precision-engineered marine transmission component designed exclusively for Mercury outboard motors, specifically tailored to models requiring a robust and reliable drive system. This pinion gear serves as a critical component within the lower unit, responsible for transferring power from the engine to the propeller shaft while maintaining optimal torque and efficiency. Crafted from high-grade, heat-treated steel, this gear is engineered to withstand the demanding stresses of continuous operation in both freshwater and saltwater environments, ensuring durability and longevity even under the most rigorous conditions. The pinion gear s precise tooth geometry and hardened surface finish minimize wear and friction, reducing the risk of premature failure and extending the operational life of the entire lower unit assembly. Whether installed in a recreational boat, a performance fishing vessel, or a commercial marine application, this component delivers seamless power transmission, contributing to smooth acceleration, improved fuel efficiency, and enhanced overall performance. Its compatibility with Mercury s proprietary lower unit design ensures a perfect fit, allowing for easy installation and maintenance without compromising the integrity of the drive system. For marine enthusiasts and professionals seeking a dependable, high-performance part, the **Mercury 43-47351 Lower Unit Pinion Gear** represents an essential upgrade or replacement solution that upholds the reliability and performance standards expected from Mercury s marine propulsion technology.

### **Pros and Cons of buying a Mercury 43-47351 Lower Unit Pinion Gear**

#### **Pros:**

The Mercury 43-47351 lower unit pinion gear is a widely used and reliable component for Mercury outboard motors, particularly in the 4.6L and 5.0L V8 models. Here are the key advantages of purchasing this part:

1. **Compatibility and Fit:** This pinion gear is specifically designed for Mercury outboards, ensuring a precise fit with minimal modifications required. It is commonly used in models such as the 4.6L and 5.0L V8 engines, including those found in Mercury Racing, Mariner, and other marine applications. The part number is well-documented, making it easier to verify compatibility before purchase.

2. **Performance and Durability:** The pinion gear is manufactured to high standards, often using hardened steel or other durable materials to withstand the stresses of marine environments. A quality pinion gear reduces wear on the lower unit s internal components, potentially extending the lifespan of the entire unit.

3. **Ease of Installation:** Since this is a standard replacement part, it is relatively straightforward to install, especially if you have basic mechanical skills or access to a marine mechanic. The lower unit is typically designed to accommodate this pinion gear without requiring extensive modifications to the housing or other components.

4. **Cost-Effective Replacement:** While the cost of the pinion gear itself may vary depending on the source, purchasing it as a standalone part is often cheaper than buying a complete lower unit. This makes it an attractive option for those who only need to replace a worn or damaged pinion gear rather than the entire lower unit.

5. **Availability of Support and Resources:** Mercury outboards have a large user community, and parts like this pinion gear are widely available through marine dealers, online retailers, and specialty marine parts suppliers. Additionally, there are numerous online forums, manuals, and tutorials that can guide you through installation and troubleshooting.

6. **Compatibility with Aftermarket Upgrades:** If you are considering performance upgrades for your outboard, such as a new propeller or a different gear ratio, this pinion gear may be compatible with those modifications. It is often used in conjunction with other aftermarket parts to optimize performance.

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#### **Cons:** While the Mercury 43-47351 pinion gear offers many benefits, there are also some potential drawbacks to consider:

1. **Potential for Counterfeit Parts:** The marine aftermarket is notorious for counterfeit or low-quality parts, especially for popular items like this pinion gear. Purchasing from untrusted sellers or unauthorized resellers may result in a part that fails prematurely or does not fit correctly. Always buy from reputable suppliers, such as official Mercury dealers, well-known online retailers, or trusted marine parts specialists.

2. **Wear on Other Components:** If the pinion gear is not properly aligned or if the lower unit s internal components (such as the drive gear or bearings) are worn, replacing just the pinion gear may not fully resolve performance issues. This could lead to additional wear on other parts, requiring further repairs down the line. A thorough inspection of the lower unit before installation is recommended.

3. **Skill and Tool Requirements:** While the installation is generally straightforward, it does require some mechanical skill and the right tools. If you are not experienced with marine engine repairs, you may need to hire a professional mechanic, which could increase the overall cost. Common tools needed include a torque wrench, lower unit puller, and possibly a gear puller or press.

4. **Limited Customization:** This pinion gear is a stock or near-stock replacement part, meaning it may not offer performance enhancements beyond what the original equipment manufacturer (OEM) intended. If you are looking for a gear with a different ratio or material for performance tuning, you may need to explore aftermarket alternatives, which could be more expensive or harder to find.

5. **Potential for Misalignment:** Improper installation or handling during the replacement process can lead to misalignment of the pinion gear with the drive gear. This can cause excessive noise, vibration, or even damage to the lower unit. Care must be taken to ensure the gear is properly seated and aligned during installation.

6. **Environmental Factors:** Marine environments are harsh, with exposure to saltwater, corrosion, and constant vibration. Even a high-quality pinion gear may degrade over time if not properly maintained. Regular lubrication, flushing of the lower unit, and inspections are essential to prolong its lifespan.

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### **Conclusion:**

The Mercury 43-47351 lower unit pinion gear is a reliable and widely used replacement part for Mercury outboards, offering compatibility, durability, and ease of installation. It is an excellent choice for those looking to replace a worn or damaged pinion gear without investing in a complete lower unit. However, potential buyers should be cautious of counterfeit parts, ensure proper installation, and consider the condition of other lower unit components. Additionally, while this part is cost-effective for basic replacements, it may not offer advanced performance tuning options.

For most DIY marine enthusiasts or those seeking a straightforward repair, this pinion gear is a solid choice. If you are unsure about installation or suspect other issues within the lower unit, consulting a marine mechanic is advisable to avoid further damage.

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### **Recommendation:**

If you have determined that the pinion gear in your Mercury outboard is worn or damaged and you are confident in your ability to perform the replacement, purchasing the **Mercury 43-47351 lower unit pinion gear** is a practical and cost-effective solution. Here s how to proceed:

1. **Verify Compatibility:** Double-check that this part number matches your specific Mercury outboard model and year. Consult your owner s manual or contact a marine parts specialist if you are unsure.

2. **Source from a Reputable Supplier:** Purchase the part from an authorized Mercury dealer, a trusted online retailer (such as Sea-Dog Marine, West Marine, or Amazon with verified sellers), or a well-reviewed marine parts store. Avoid purchasing from unknown sellers to avoid counterfeit or low-quality parts.

3. **Inspect the Lower Unit:** Before installation, inspect the lower unit for signs of wear, corrosion, or damage to other components (such as the drive gear, bearings, or seals). If other parts are degraded, consider replacing them simultaneously to prevent future issues.

4. **Gather Tools and Follow Instructions:** Ensure you have the necessary tools, including a lower unit puller, gear puller or press, and a torque wrench. Follow the manufacturer s installation instructions or a reputable online guide (such as those from Mercury or marine forums) to avoid misalignment or damage during installation.

5. **Consider Professional Help if Needed:** If you are not experienced with marine engine repairs, do not hesitate to consult a professional mechanic. Improper installation can lead to costly repairs or even damage to the outboard.

6. **Maintain the Lower Unit:** After installation, follow your outboard manufacturer s maintenance guidelines, including regular flushing of the lower unit, checking oil levels, and inspecting for leaks or unusual noises during operation.

By following these steps, you can successfully replace the pinion gear and restore or improve the performance of your Mercury outboard. For most users, this part is a reliable and worthwhile investment.

Details:

Good used Mercury OEM Lower Unit Pinion Gear 43-47351.

part #: 4347351 price

  • $45.00

specifications ouboaen:

  • for makes: Mercury
  • mpn: 43-47351
  • part type: Pinion Unit Gear
  • country of origin: United States

shipping ouboaen:

  • class: Economy
  • type: Fixed
  • service: Economy
  • cost: $0.00
  • transit: 4-9 Days

offer ouboaen:

  • quantity: 1
  • started: May 2, 2026
  • options: Ship-to-home
  • availability: In Stock
  • sold: 0

payments ouboaen:

  • credit card: Discover
  • other
  • wallet: Apple-pay

seller ouboaen:

  • rating: 99.9%
  • city: Clarksville, Michigan
  • # reviews: 726

returns ouboaen:

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

general ouboaen:

  • Boat Parts > Outboard Engines Components > Lower Unit Components
  • condition: Used
for makes: mercury, part type: pinion unit gear, country of origin: united states,
category: boat parts > outboard engines components > lower unit components, sku: 23684905384509793,
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1 offer $45.00 USD
  • Used. Offer #1 priced at $45.00 + $0.00 shipping estimate = $45.00* total. FREE SHIPPING

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