1. Boat Outboard Engines To Buy
  2. sku: 24138710433639751
  3. MERCURY 27-840940

MERCURY 27-840940 Gasket

fits model: Marine. make: Mercury.

27-840940 Mercury Marine Gasket

( Manufacturer Part Number: 27-840940 ), ( Part Type: Gasket )

Review MERCURY Gasket fits MARINE

The **Mercury 27-840940 Marine Gasket** is a high-performance, precision-engineered sealing component designed specifically for Mercury outboard motors, ensuring optimal engine protection and reliability in demanding marine environments. Crafted from durable, high-grade **EPDM (Ethylene Propylene Diene Monomer) rubber**, this gasket is engineered to withstand extreme temperatures, exposure to saltwater, UV radiation, and constant mechanical stress, making it an indispensable part of your engine s sealing system. Its robust construction prevents fluid leaks whether oil, coolant, or fuel while also acting as a barrier against contaminants like water, debris, and corrosion, thereby extending the lifespan of critical engine components. The gasket features a **tight, interference-fit design** with strategically placed ridges and grooves, allowing it to conform seamlessly to the mating surfaces of the engine s lower unit and powerhead, ensuring a leak-proof seal under pressure. Ideal for use in **Mercury outboards ranging from 40 to 250 horsepower**, this gasket is compatible with models like the **Mercury 40 150 HP Verado, 150 250 HP Verado, and 40 150 HP FourStroke** series, among others, making it a versatile solution for both new installations and routine maintenance. Whether you're preparing for a season of fishing, cruising, or high-performance racing, this gasket delivers the durability and performance needed to keep your engine running smoothly, reducing the risk of costly repairs and downtime. Proper installation, following Mercury s recommended procedures, is essential to maximize its effectiveness and ensure long-term reliability.

**Pros and Cons of buying a Mercury 27-840940 Marine Gasket**

The **Mercury 27-840940** is a gasket designed for use in Mercury outboard engines, specifically for the **200 400 HP series** (commonly found in models like the 250, 300, and 400 HP). Below is a detailed breakdown of its advantages and disadvantages.

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### **Pros**

1. **OEM Compatibility**

The gasket is manufactured to **original equipment manufacturer (OEM) specifications**, ensuring a precise fit for Mercury outboards. This reduces the risk of leaks or improper sealing, which can cause engine damage if not installed correctly.

2. **High-Quality Materials**

Mercury uses **durable, heat-resistant materials** in their gaskets, designed to withstand the thermal and mechanical stresses of marine engine operation. This improves longevity compared to generic or aftermarket alternatives that may degrade faster.

3. **Reliability and Performance**

Since it is a **factory-recommended part**, it is tested for compatibility with Mercury s engine systems, including fuel injection, cooling, and lubrication pathways. This minimizes the risk of performance issues or failures during use.

4. **Ease of Installation**

The gasket is **pre-cut and designed for straightforward replacement**, reducing the complexity of the installation process compared to custom-cut gaskets. This can save time and labor costs, especially for DIYers.

5. **Warranty Coverage**

Purchasing directly from Mercury or an authorized dealer may include **warranty protection**, providing peace of mind in case of defects. Some dealers also offer return policies if the part is damaged upon arrival.

6. **Prevents Long-Term Damage**

A failing gasket can lead to **coolant leaks, oil contamination, or overheating**, which can cause severe engine damage. Replacing it with an OEM part helps maintain engine integrity and extends its lifespan.

7. **Consistency Across Models**

The 27-840940 is part of Mercury s standardized gasket line, meaning it is **easily replaceable** if the engine undergoes future repairs or upgrades, ensuring parts availability.

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### **Cons**

1. **Higher Cost Compared to Aftermarket Alternatives**

OEM parts are typically **more expensive** than generic or third-party gaskets. For budget-conscious buyers, aftermarket options (from brands like **Sealmaster, Flexitallic, or Gasket Pro**) may offer similar performance at a lower price.

2. **Limited Availability Outside Authorized Dealers**

While Mercury parts are widely available, some **specialty or online retailers** may not stock this specific gasket, requiring purchases from dealers or official distributors, which could involve shipping delays or higher fees.

3. **Potential Overkill for Minor Repairs**

If the gasket failure is isolated (e.g., only one section is leaking), some mechanics might argue that **replacing only the damaged portion** (if possible) would be more cost-effective than a full gasket swap. However, Mercury often recommends full replacement for reliability.

4. **Installation Requires Expertise**

While the gasket itself is easy to install, **proper removal of old gasket material, surface preparation, and torque specifications** are critical to prevent leaks. Improper installation can void warranties or lead to future issues.

5. **Environmental and Disposal Concerns**

Like all engine parts, gaskets contain materials that may require **proper disposal** (e.g., recycling or hazardous waste handling). Buyers must ensure they dispose of the old gasket responsibly, which can be an inconvenience.

6. **Risk of Counterfeit Parts**

Purchasing from **unauthorized sellers** (e.g., eBay, Amazon, or unscrupulous online marketplaces) increases the chance of receiving **fake or substandard gaskets**. Always buy from **verified Mercury dealers or reputable marine supply stores** to avoid this risk.

7. **Not Universal Across All Mercury Models**

While this gasket fits a range of 200 400 HP engines, **specific model years or variations** (e.g., 2010 vs. 2020) may require slight adjustments or additional parts. Double-checking the **engine model and year** before purchase is essential.

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### **Conclusion**

The **Mercury 27-840940 gasket** is a **reliable, high-quality choice** for maintaining or repairing Mercury outboard engines, particularly for those who prioritize **OEM compatibility, durability, and long-term performance**. Its advantages in **fitment, material quality, and warranty support** make it a strong option for serious boaters or those who prefer factory-backed parts.

However, the **higher cost and potential overkill for minor repairs** may deter budget-conscious buyers. If the primary concern is **cost savings**, aftermarket gaskets from trusted brands could be a viable alternative **but only if they meet Mercury s specifications**. Additionally, **proper installation is non-negotiable**, so buyers should either **DIY carefully** or consult a professional mechanic.

For most **performance-oriented or high-mileage boats**, the **Mercury 27-840940 remains the safest and most effective choice**, balancing reliability with long-term engine protection.

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### **Recommendation**

- **Buy from an authorized Mercury dealer or a reputable marine parts supplier** (e.g., **West Marine, Sea-Doo/Mercury dealers, or online retailers like BoatUS or Mercruiser Outboards**) to ensure authenticity.

- **Verify the exact engine model and year** before purchasing to confirm compatibility.

- **If on a tight budget**, compare aftermarket options (e.g., **Sealmaster 1000 or Flexitallic**) but **ensure they are rated for marine use and meet Mercury s standards**.

- **Consider professional installation** if unsure about removing old gasket material or achieving proper sealing.

- **Replace the gasket as part of a full engine service** (e.g., during a tune-up or overhaul) to maximize reliability and prevent future issues.

**Final Verdict:** The **Mercury 27-840940 is the best choice for OEM reliability**, but weigh the cost against aftermarket alternatives if budget is a concern. Always prioritize **quality and proper installation** to avoid costly engine damage.

Details:

New OEM Mercury Marine Gasket.

part #: 27840940 prices

  • $36.18-$41.95

specifications ouboaen:

  • for models: Marine
  • for makes: Mercury
  • mpn: 27-840940
  • part type: Gasket

seller ouboaen:

  • rating: 100.0%
  • # reviews: 871
  • city: Harrison Township, Michigan

general ouboaen:

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

shipping ouboaen:

  • type: Calculated
  • cost: $7.42
  • class: Standard
  • transit: 5-9 Days
  • carrier: USPS
  • service: USPS Ground Advantage

payments ouboaen:

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

returns ouboaen:

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

offer ouboaen:

  • started: May 23, 2026
  • quantity: 2
  • sold: 0
  • options: Ship-to-home
  • availability: In Stock
  • best offers: True
for models: marine, for makes: mercury, part type: gasket,
category: boat parts > outboard engines components, sku: 24138710433639751,
Mercury 27-840940 Is Similar To:
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3 offers $36.18–$41.95 USD
  • New. Offer #1 priced at $40.00 + $7.42 shipping estimate = $47.42* total. New OEM Mercury Marine Gasket.+$7.42 shipping
  • New. Offer #2 priced at $41.95 + $9.00 shipping estimate = $50.95* total. 600 SCi - 0M952908 THRU 0M962885. 525 EFI - 0M900146 THRU 0M953619.+$9.00 shipping
  • New. Offer #3 priced at $36.18 + $18.25 shipping estimate = $54.43* total. +$18.25 shipping

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