SKU: 25970192706

Gearcase Seal Kit – Fits Mercury/Mariner 175-300HP V6/V8 Outboards (Replaces 8M0142979)

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Description

Gearcase Seal Kit – Fits Mercury/Mariner 175-300HP V6/V8 Outboards (Replaces 8M0142979)Gearcase Seal Kit Fits Mercury Mariner 175 300HP V6 V8 Outboards (Replaces 8M0142979) This gearcase seal kit is designed for Mercury Marine 175 300HP 3. 4L V6 and 4. 6L V8 PRO XS Verado outboard engines. It provides the necessary components to reseal the lower unit, preventing water intrusion and oil leaks. This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring a precise fit and reliable performance for a wide

Gearcase Seal Kit – Fits Mercury/Mariner 175-300HP V6/V8 Outboards (Replaces 8M0142979)

This gearcase seal kit is designed for Mercury Marine 175-300HP 3.4L V6 and 4.6L V8 PRO XS / Verado outboard engines. It provides the necessary components to reseal the lower unit, preventing water intrusion and oil leaks.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring a precise fit and reliable performance for a wide range of compatible engine models.

  • Installation: Direct OEM-spec replacement.
  • Function: Seals the gearcase to protect internal components from water and contaminants.
  • Weight: 0.57 lbs (0.26 kg).

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Brand Part Number
Mercury Marine 8M0142979
Mercury 26-8M0142979
WSM 26-8M0142979
GLM Marine 87532
Recmar REC26-8M0142979

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Brand Model Rated HP Stroke OEM Part No. Notes
Mercury/Mariner V6 3.4L 175 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V6 3.4L 200 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V6 3.4L 225 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V8 4.6L 200 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V8 4.6L 225 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V8 4.6L 250 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V8 4.6L 300 4-Stroke 8M0142979 Pro XS / Verado
Mercury/Mariner V8 Racing 300R 4-Stroke 8M0142979 From S/N 1E080500
Mercury/Mariner V8 Racing AMS Racing 4-Stroke 8M0142979 From S/N 1E081459

Technical Specifications

Specification Value
Product Type Gearcase Seal Kit
Installation Direct OEM replacement
Weight 0.57 lbs (0.26 kg)

Installation Guide

  1. Drain the gearcase lubricant completely by removing the drain and vent screws.
  2. Remove the propeller and any associated hardware.
  3. Unbolt and carefully separate the lower unit (gearcase) from the outboard's midsection.
  4. Disassemble the gearcase components as required to access the propeller shaft and driveshaft seals.
  5. Carefully extract all old seals and O-rings from their housings, taking care not to scratch the sealing surfaces.
  6. Thoroughly clean all components and sealing surfaces of old sealant, oil, and debris.
  7. Lubricate the new seals with marine grease and press them into place using a suitable seal driver or socket.
  8. Reassemble the gearcase, ensuring all components are installed correctly and bolts are torqued to manufacturer specifications.
  9. Re-install the lower unit onto the engine.
  10. Refill the gearcase with the manufacturer-recommended lubricant to the proper level.

Troubleshooting & FAQ

How do I confirm this seal kit fits my Mercury engine?
Verify your engine's model and horsepower rating against the "Compatible Engine Models" table. For V8 Racing models, it is critical to confirm your serial number is 1E080500 or newer, and for AMS Racing models, 1E081459 or newer. Always cross-reference the OEM part number, 8M0142979 or 26-8M0142979, with your engine's service manual to ensure an exact match.

What are the common signs that my gearcase seals are failing?
The most common sign is milky or water-contaminated gear lube when you drain it. Other symptoms include visible oil leaking from the propeller shaft area or a persistent sheen of oil on the water around your lower unit after it has been sitting.

Is any special tool required for installation?
While basic hand tools are sufficient for disassembly, using a dedicated seal puller and a proper seal driver (or a socket of the exact correct diameter) is highly recommended. This ensures the old seals are removed and new seals are installed without damaging the seal or its housing, preventing future leaks.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

  • Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
  • This product is an aftermarket replacement part and is not an OEM component.
  • Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

  • Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
  • Fast Global Shipping: Free delivery worldwide in 5–15 days.
  • Direct from Manufacturer: Competitive pricing without compromising quality.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 25970192706

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Dan Che
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★★★★★ 5
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Size: 9, Color: Brown, Size: 9, Color: Brown
I recently purchased size 9 of these shoes, and they exceeded my expectations in every way! Here’s what I love about them: 1. Comfort: The moment I put them on, I noticed how soft and supportive they felt. The cushioning provides all-day comfort, making them perfect for long walks, workdays, or running errands. 2. Fit: The sizing is spot-on! I ordered my usual size, and they fit perfectly with no need to size up or down. There’s enough room for my toes to move without feeling too loose or tight. 3. Style: These shoes look even better in person. The design is sleek and versatile, making them easy to pair with both casual and semi-formal outfits. I’ve received several compliments already! 4. Durability: I put it on the day of purchase. After wearing them daily for a couple of days, they still look brand new. The stitching and material seem high-quality and built to last. 5. Value for Money: For the price, these shoes deliver exceptional value. You’re getting premium comfort and style without breaking the bank. Final Thoughts: If you’re looking for shoes that offer comfort, style, and durability, I highly recommend giving these a try. I’ll definitely be considering another pair in a different color soon! To conclude, I’m very happy for this purchase. Will definitely buy again.
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Reviewed in the United States on January 13, 2025
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Roderick
Natrona Heights, US
★★★★★ 5
Great Purchase
Size: 12, Color: Black
These shoes are great. They look great and extremely comfortable.
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Reviewed in the United States on May 10, 2026
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Isaiah O
Alexandria, US
★★★★★ 5
Comfortable, Easy to Clean, and Held Up at Coachella
Size: 12, Color: White, Size: 12, Color: White
I’m really happy with this purchase. The shoes are very comfortable, and the product description is accurate. I followed the sizing recommendation based on my foot type and went one size up—they fit perfectly. I bought these for Coachella, and they definitely held up. I was on my feet all day, and they stayed comfortable the entire time. What impressed me most is how easy they were to keep clean. At the end of each day, I was able to wipe them down and maintain their whiteness without much effort. Once I got home, I gave them a deeper clean, and they honestly looked as good as new. Even the laces cleaned up easily. Now I’ve transitioned them into my regular work shoes, and they still look great. Overall, I’m very satisfied with this purchase and would definitely recommend them.
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Reviewed in the United States on May 4, 2026
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Hawaiian
Dallas, US
★★★★★ 4
Great shoes that are well made, lite weight, and comfortable.
Size: 12, Color: Brown
Just received my 2nd pair of shoes from Bruno Marc in a size 12. These are really lite and comfortable. It can be dressed down to be a casual shoe or dressed up with a nice suit. These run true to size so I ordered my usual size 12 and the fit was perfect. Being my 2nd pair of Bruno Marc's, I like the quality of their shoes and each shoe is described appropriately on fit and comfort. Insole of these shoes were awesome and provided soft comfort on the feet along with a slight arch support too. Will definitely consider ordering more Bruno Marc shoes in the future.
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Reviewed in the United States on March 11, 2025
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JCMIV63
New York, US
★★★★★ 5
Cushioned, comfortable, stylish and a rubber sole!
Size: 10, Color: Brown
These shoes check multiple boxes for me, comfortable, cushioned, rubber sole and stylish. As my feet grow old and worn out, I'm on a constant search for comfortable, cushioned shoes that are suitable for work and dressier occasions. I have tried many expensive shoes that look great but either lack cushioning, arch support and or comfort. One of the nice things is these shoes have a rubber sole, where most cushioned shoes have the foam soles which are great, but they tend to lack grip particularly when its damp/wet. They have average arch support, but the insole is removable and I put my own cushioned arch support. Love these!
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