Sierra 18-2767 Transom Seal
Sierra 18-2767 Transom Seal Product Description
Understanding the Role of Your Boat's Transom Seal
In the world of boating, keeping water where it belongs—outside the hull—is crucial for safety, performance, and longevity. The transom seal acts as a vital barrier, sealing the gap where your outboard or sterndrive mounts to the transom. Without a reliable seal, saltwater or freshwater can seep into the bilge, leading to corrosion, electrical shorts, and costly repairs. The Sierra 18-2767 steps in as a dependable solution, crafted to restore that watertight integrity with precision engineering.
Boat owners often overlook this component until leaks appear, but proactive replacement during routine maintenance can prevent bigger headaches. Whether you're dealing with a weathered seal from years of sun exposure or preparing for a new season on the water, this part delivers the protection your vessel needs.
Key Features That Set the Sierra 18-2767 Apart
- Durable Construction: Made from high-grade neoprene or rubber compounds resistant to UV rays, ozone, and harsh marine environments, ensuring it withstands the elements better than stock options.
- Precise Fit: Designed as a direct aftermarket equivalent, it molds seamlessly to common transom assemblies without modifications.
- Enhanced Sealing: Multi-layer design compresses evenly under bolt torque, creating a superior water barrier that reduces vibration and noise transmission.
- Easy Maintenance: Simple to inspect and replace, saving time during haul-outs or winterizations.
These attributes make it a favorite among DIY boaters and professional mechanics alike, offering OEM-level performance at a fraction of the hassle.
Signs Your Transom Seal Needs Replacement
Spotting issues early can save your engine from submersion damage. Watch for these telltale symptoms:
- Persistent water in the bilge, even after pumping, especially after trailering or rough seas.
- Visible cracks, hardening, or swelling around the transom mounting area.
- Rust stains or corrosion on the engine's lower unit or transom brackets.
- Unusual bilge pump cycling or a musty odor inside the boat.
- Vibration or play in the outboard mount that wasn't there before.
Addressing these promptly with the Sierra 18-2767 prevents escalation, keeping your boating adventures uninterrupted.
Step-by-Step Installation Guide for DIY Success
Replacing a transom seal is a straightforward job that most boaters can tackle in an afternoon. Here's a proven approach:
- Prep the Area: Tilt the engine up, support it securely, and remove the mounting bolts. Clean the transom surfaces thoroughly with a marine degreaser to remove old sealant residue.
- Position the Seal: Align the new Sierra 18-2767 precisely over the mounting holes. Dry-fit first to ensure no twists or gaps.
- Apply Sealant: Use a marine-grade polyurethane sealant on the transom side for extra adhesion. Avoid over-applying to prevent squeeze-out issues.
- Reinstall Engine: Lower the engine into place, hand-tighten bolts, then torque to manufacturer specs in a crisscross pattern. Double-check for level alignment.
- Test Thoroughly: Launch in shallow water, run the engine at idle, and inspect for leaks over several outings.
Pro Tip: Always work with the boat out of the water and engine drained to avoid surprises. Common pitfalls include uneven torquing, which can warp the seal, or skipping the cleaning step, leading to poor adhesion.
Maintenance Tips to Extend Seal Life
To maximize the lifespan of your Sierra 18-2767 transom seal:
- Inspect annually during winter storage, feeling for brittleness or checking for compression set.
- Rinse with fresh water after saltwater use to flush away corrosive salts.
- Avoid overtightening bolts, which can crush the material prematurely.
- Apply a UV protectant spray if the boat sits dockside for extended periods.
These habits can double the service interval, turning a routine part into a long-term asset.
Why Boaters Trust Sierra Engine Parts
Sierra has built a reputation for aftermarket excellence by reverse-engineering OEM designs with rigorous testing. Their parts undergo real-world abuse in labs simulating waves, salt spray, and temperature swings. Unlike generics, Sierra components prioritize fit, function, and reliability, earning nods from marinas nationwide. Choosing Sierra means fewer comebacks and more time enjoying the water.
Frequently Asked Questions
What is the primary function of a transom seal like the Sierra 18-2767?
It prevents water intrusion through the transom where the outboard or sterndrive mounts, protecting the bilge, wiring, and engine components from corrosion and flooding.
How do I know if my current transom seal is failing?
Look for bilge water accumulation without rain, visible cracks or deterioration, corrosion on mounts, or increased bilge pump activity.
Is the Sierra 18-2767 suitable for DIY installation?
Yes, it's designed for straightforward replacement. With basic tools and following torque specs, most boaters can complete it in under two hours.
What materials make the Sierra 18-2767 durable?
Premium neoprene or rubber blends offer resistance to UV, ozone, chemicals, and compression, outperforming many factory seals in harsh conditions.
Can a bad transom seal damage my boat's engine?
Absolutely—water leaks can submerge electrical systems, cause shorts, and accelerate corrosion, potentially leading to engine failure if ignored.
How often should I replace my transom seal?
Inspect every season; replace every 3-5 years or sooner if signs of wear appear, especially in saltwater environments.
Does the Sierra 18-2767 reduce engine vibration?
Yes, its precise fit and resilient material help dampen vibrations, improving ride comfort and reducing stress on mounts.
Save $17 when you buy the Sierra 18-2767 Transom Seal for only $144 from NVN Marine! Same day shipping before 3pm.
Sierra 18-2767 Transom Seal Technical Specifications
| Type: | |
|---|---|
| Vendor: |
Sierra Engine Parts |
| Weight: |
2.16 lb |
| Description: |
OMC Sterndrive/Cobra - 120 hp & Up ('67-'77) |
| Replaces: |
313080 |
Sierra 18-2767 Transom Seal User Reviews
Sierra 18-2767 Transom Seal Shipping & Return
| Shipping Weight: |
2.16 lb |
|---|---|
| Box Sizes: |
2.00 (h) x 19.00 (w) x 19.00 (l) |
| Cubic Feet: |
722.0 |
| Returnable: |
Yes |
For detailed shipping policy please check our Shipping Policy and you can find our Return and Refund Policy here.



