MERCURY 85964A1 Thrust Hub Washer Prop Nut 64075A1

( Manufacturer Part Number: 85964A1 ), ( Part Type: Hp Hub Washer Prop )

Review MERCURY Hp Thrust Hub Washer Prop Hardware Nut fits 200 1981–2020

The **Mercury 85964A1 1981 200 Series 20 HP Thrust Hub Washer Prop Nut** is a precision-engineered marine hardware component designed specifically for Mercury outboard motors from the early 1980s, particularly those in the iconic **200 Series 20 HP** lineup. This high-quality prop nut, identified by its part number **64075A1**, serves as a critical fastening element in the propulsion system, ensuring secure attachment of the propeller shaft to the thrust hub assembly. Crafted from durable, corrosion-resistant materials, this nut is built to withstand the demanding conditions of saltwater environments, where exposure to moisture, salt, and constant mechanical stress can quickly degrade inferior components. Its robust construction features a **fine-threaded design** optimized for a tight, vibration-resistant fit, preventing loosening during high-performance operation or rough water conditions. The **thrust hub washer** integrated into the nut distributes load evenly across the shaft and housing, reducing wear on the propeller assembly and minimizing the risk of premature failure. This part is essential for maintaining optimal performance, efficiency, and safety in marine applications, making it a must-have replacement for boat owners seeking to preserve the reliability of their Mercury outboards. Whether restoring a classic vessel or upgrading an existing setup, this **OEM-quality prop nut** ensures a secure, long-lasting connection between the propeller and the engine, delivering peace of mind for both recreational and light-duty commercial use.

### **Pros and Cons of buying a Mercury 85964A1 (1981 200 20 HP Thrust Hub Washer Prop Nut 64075A1)**

1. **Direct Compatibility** This part is designed specifically for the 1981 Mercury 200 20 HP outboard motor, ensuring an exact fit without modifications. This reduces the risk of improper installation or performance issues.

2. **Authentic Replacement** The thrust hub washer and prop nut (64075A1) are original Mercury components, meaning they meet the manufacturer s specifications for durability and function. Using genuine parts helps maintain the motor s reliability.

3. **Prevents Propeller Damage** A worn or missing thrust washer can cause excessive vibration or improper alignment, leading to propeller damage over time. Replacing this part helps preserve the propeller s integrity.

4. **Easier Maintenance** Since the part is readily available (assuming it s still in production or sourced from a reputable dealer), replacing it is straightforward compared to sourcing aftermarket alternatives that may not fit perfectly.

5. **Long-Term Reliability** Mercury outboards are known for durability, and using OEM parts helps sustain the motor s performance and longevity, reducing the likelihood of premature wear or failure.

6. **Warranty Considerations** If the motor is still under warranty (or if the part is covered under a separate warranty), using an original Mercury part ensures compliance with warranty terms, preventing voidance due to non-genuine replacements.

1. **Cost** Original Mercury parts can be more expensive than aftermarket alternatives. While this may not be a significant factor for a single component, the cumulative cost of using only OEM parts over time can add up.

2. **Limited Availability** Depending on the age of the motor or the part s production status, finding the exact 85964A1 thrust hub washer and 64075A1 prop nut may require ordering from a specialty dealer or Mercury service center, which could involve shipping delays.

3. **Potential Overkill for Minor Issues** If the thrust hub washer or prop nut is only slightly worn and not causing immediate problems, replacing it may be unnecessary. In such cases, the cost and effort might not justify the upgrade.

4. **No Performance Upgrade** This part does not enhance the motor s power, efficiency, or speed; it simply restores or maintains functionality. If you re looking for performance improvements, this replacement alone won t provide them.

5. **Installation Requires Skill** While the part is straightforward to install, improper handling (e.g., overtightening the prop nut or misaligning the thrust washer) can damage the motor or propeller. If you re not experienced with outboard maintenance, hiring a professional may incur additional labor costs.

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### **Conclusion**

The **Mercury 85964A1 thrust hub washer and 64075A1 prop nut** is a **practical and reliable choice** for maintaining or restoring your 1981 Mercury 200 20 HP outboard motor. The benefits of using an original part such as exact fit, warranty compliance, and long-term reliability outweigh the minor drawbacks (cost and potential overkill for minor wear). If the part is genuinely needed to prevent further damage or ensure proper motor function, investing in this OEM component is a sound decision.

However, if you re on a tight budget or the part is only slightly degraded, you could consider **high-quality aftermarket alternatives** (e.g., from brands like **Mercury Marine, Seafoam, or reputable marine suppliers**) that offer comparable performance at a lower cost. Always verify compatibility and reviews before opting for non-OEM parts.

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- The part is visibly worn, damaged, or missing.

- You prioritize authenticity and warranty compliance.

- You re comfortable with the cost and want to ensure long-term motor health.

- The part is only minimally worn and the motor is functioning fine.

- You re open to aftermarket options that offer similar performance at a lower price.

- You re unsure about installation and prefer professional help (in which case, the cost may not be a significant concern).

For most cases where the part is necessary for proper motor operation, **the original Mercury component is the best choice**. Always pair this replacement with routine maintenance (e.g., checking propeller alignment, inspecting the lower unit, and using appropriate lubricants) to maximize the motor s lifespan.

Details:

1981 Mercury 200 20 HP 85964A1 Thrust Hub Washer Prop Hardware nut 64075A1, 34237, 27023, 65439, 89103, Off of a Mercury hp 2 stroke outboard motor.

part #: 85964a1 prices

• $7.00-$12.99

specifications ouboaen:

• for models: 200
• for makes: Mercury
• for years: 1981-2020
• mpn: 85964a1
• part type: Hp Hub Washer Prop

offer ouboaen:

• availability: In Stock
• started: April 12, 2026
• sold: 0
• options: Ship-to-home
• quantity: 1

general ouboaen:

• condition: Used
• Boat Parts > Outboard Engines Components > Other

payments ouboaen:

• other
• wallet: Google-pay
• credit card: Visa

seller ouboaen:

• # reviews: 1382
• city: O'Fallon, Missouri
• rating: 99.6%

returns ouboaen:

• policy: No Returns

shipping ouboaen:

• transit: 4-8 Days
• service: USPS Ground Advantage
• carrier: USPS
• type: Fixed
• class: Standard
• cost: $5.99

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