Keep your Yamaha outboard running cool under pressure with the Sierra 18-3465 water pump repair kit. Designed as a direct replacement for the OEM 3465 impeller assembly, this kit tackles the most common culprit of engine overheating: a worn-out water pump. Whether you're prepping for a weekend on the lake or tackling offshore adventures, refreshing your water pump prevents costly downtime and protects your investment.

Key Components for Reliable Performance

This all-in-one repair kit includes everything needed for a complete water pump rebuild:

• High-quality neoprene impeller for superior flexibility and longevity in saltwater environments.
• Precision-machined wear plate to ensure optimal impeller clearance and maximum water flow.
• Durable key, liner, and O-rings that resist cracking and swelling from prolonged exposure to fuels and oils.
• Gaskets and housing components engineered to match factory specs for a seamless fit.

Unlike basic impeller-only kits, Sierra's comprehensive design restores full pump efficiency, mimicking the original equipment's cooling capacity.

Perfect Fit for Popular Yamaha Models

Engineered for compatibility across a wide range of Yamaha 2-stroke and 4-stroke outboards, this kit suits models from 40HP to 90HP, including Enduro and Sport variants. It's a go-to solution for engines prone to impeller degradation due to dry running, age, or debris ingestion. Always cross-check your service manual to confirm fitment, as lower units can vary by year and serial number.

Why Boaters Trust Sierra Over Stock Parts

Sierra draws from decades of marine engineering expertise to deliver parts that exceed OEM standards in material resilience. Users report this kit lasting seasons longer than generics, thanks to its UV-stabilized rubber and corrosion-resistant hardware. It's not just a fix—it's an upgrade that boosts cooling efficiency, reducing the risk of vapor lock or seized pistons during hot summer runs.

Step-by-Step Rebuild Tips for DIY Success

Rebuilding your water pump takes about an hour with basic tools. Here's a pro mechanic's guide:

1. Prep safely: Disconnect the battery, flush the cooling system, and remove the lower unit gearcase.
2. Disassemble: Pry out the old impeller using needle-nose pliers—twist gently to avoid damaging the housing.
3. Clean thoroughly: Remove grit and scale with a non-abrasive cleaner; inspect the housing for scoring.
4. Install new parts: Lubricate with Yamaha-compatible waterproof grease, align the impeller key, and torque to spec.
5. Test run: Prime the pump by matting the impeller, then check for strong pee stream at idle.

Pro tip: Replace every 2-3 years or 200 hours, especially if you trailer frequently or run in silty waters.

Extend Your Outboard's Life with Proactive Cooling

Beyond the kit, maintain peak performance by monitoring tell-tale flow, using ethanol-free fuel, and winterizing properly. This repair isn't just reactive—it's preventive maintenance that keeps you on the water, not in the shop.