Sierra 18-2029 321481 OMC Seal 55-068
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Sierra 18-2029 321481 OMC Seal 55-068 Product Description
Understanding the Sierra 18-2029 OMC Seal: A Reliable Replacement for 321481 and 55-068
Boat owners know that seals play a critical role in keeping outboard motors running smoothly, preventing oil leaks and water intrusion that can lead to costly repairs. The Sierra 18-2029 stands out as a direct aftermarket equivalent to the OMC 321481 and 55-068 seals, designed specifically for demanding marine environments. Crafted from high-grade materials, this seal ensures a tight, durable barrier around crankshafts and other vital components, helping maintain optimal engine pressure and lubrication.
Perfect Fit for OMC and Johnson/Evinrude Engines
This seal fits a wide range of OMC-powered outboards, including popular Johnson and Evinrude models from the 1960s through the 1980s. Mechanics often reach for it when servicing 40hp to 140hp two-stroke engines, where lower unit or powerhead seals wear out from constant exposure to saltwater, fuel mixtures, and vibration. Verify your engine's service manual for exact match, but it's a go-to for cross-referencing OMC part 55-068 in rebuild kits.
- Replaces OMC 321481 and 55-068 seamlessly
- Ideal for inline and V4 configurations
- Compatible with freshwater and saltwater applications
Key Features That Set Sierra 18-2029 Apart
What makes this seal more than just a replacement? Sierra engineers focus on enhanced lip design for better sealing under high RPMs, using nitrile rubber that's resistant to ethanol-blended fuels common today. Unlike some generics, it resists hardening and cracking from UV exposure during storage, extending service life on the water.
| Feature | Benefit |
|---|---|
| Precision-molded dimensions | Drop-in installation without modifications |
| Oil- and fuel-resistant compound | Handles modern gas additives without swelling |
| High-temperature tolerance | Stays pliable in hot engine bays |
Step-by-Step Installation Tips for DIY Enthusiasts
Installing the Sierra 18-2029 doesn't require a full teardown. Start by draining the lower unit oil and removing the water pump housing or gearcase as needed. Clean mating surfaces thoroughly to remove old sealant residue—use a plastic scraper to avoid gouging aluminum. Lightly lube the outer edge with marine grease, then press into place using a seal driver tool sized to the shaft diameter. Torque adjacent bolts to spec, and run a compression test post-install to confirm no leaks.
- Disconnect battery and tilt motor for access
- Inspect shaft for scoring; hone if necessary
- Align seal lip away from rotation direction
- Reassemble and check for smooth propeller spin
Pro Tip: Always pair with fresh gear lube and inspect nearby bearings—worn ones accelerate seal failure.
Maintenance Best Practices to Maximize Longevity
Extend the life of your Sierra 18-2029 by flushing the engine after every saltwater outing. Monitor for milky gear oil, a telltale sign of seal breach. Annual inspections during winterization catch issues early, saving you from trailering breakdowns. Boat shop veterans swear by this seal for its balance of affordability and reliability in high-use recreational fleets.
Why Sierra Engine Parts Deliver Trusted Performance
Sierra's reputation in the marine aftermarket comes from rigorous testing against OEM standards, often exceeding them in abrasion resistance. Boaters choose it over pricier originals because it restores factory sealing without the premium markup, backed by widespread use in repair yards from the Great Lakes to the Gulf Coast.
Frequently Asked Questions
What does the Sierra 18-2029 seal replace?
It directly replaces OMC part numbers 321481 and 55-068, commonly used in Johnson and Evinrude outboard lower units and powerheads.
Is the Sierra 18-2029 suitable for two-stroke engines?
Yes, it's optimized for two-stroke OMC engines from 40hp to 140hp, handling the heat and oil mix effectively.
How do I know if my seal needs replacing?
Look for gear oil leaks, water contamination in the oil, or unusual gear whine. Visual cracks on removal confirm wear.
Can I install this seal myself?
Absolutely, with basic tools like a seal driver and torque wrench. Follow your service manual for torque specs.
Does it work with ethanol fuels?
Yes, the nitrile material resists swelling from E10 and higher blends, unlike older seals.
What's the expected lifespan of this seal?
Under normal use, 2-5 years or 500+ hours, depending on maintenance and water conditions.
Is it interchangeable with other brands?
It matches dimensions of many aftermarket seals but always cross-check part numbers for your model.
Save $3 when you buy the Sierra 18-2029 321481 OMC Seal 55-068 for only $13 from NVN Marine! Same day shipping before 3pm.
Sierra 18-2029 321481 OMC Seal 55-068 Technical Specifications
| Type: | |
|---|---|
| Vendor: |
Sierra Engine Parts |
| Weight: |
0.03 lb |
Sierra 18-2029 321481 OMC Seal 55-068 User Reviews
Sierra 18-2029 321481 OMC Seal 55-068 Shipping & Return
| Shipping Weight: |
0.03 lb |
|---|---|
| Box Sizes: |
1.00 (h) x 4.00 (w) x 5.00 (l) |
| Cubic Feet: |
20.0 |
| Returnable: |
Yes |
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