Sierra 18-3429 3429 Yamaha Water Pump Repair Kit
Sierra 18-3429 3429 Yamaha Water Pump Repair Kit Product Description
Revive Your Yamaha Outboard's Cooling System with Confidence
Keeping your Yamaha outboard motor running cool under pressure is non-negotiable, especially during those long days on the water. The Sierra 18-3429 water pump repair kit steps in as a reliable fix when wear and tear starts showing—think diminished water flow, overheating warnings, or unusual engine temps. This kit rebuilds the impeller housing and related components to factory specs, restoring efficient cooling without the hassle of a full pump replacement.
What sets this apart? Sierra crafts these kits with durable materials that mimic OEM performance, using premium rubber impellers resistant to deformation and corrosion from saltwater exposure. Boat owners rave about the straightforward rebuild process that gets you back fishing or cruising faster, saving time and frustration compared to piecemeal part hunting.
Key Components for a Complete Rebuild
- High-Quality Impeller: Flexible yet tough neoprene construction handles high RPMs and varying water conditions.
- Precision Wear Plate: Ensures smooth impeller operation and prevents premature wear.
- Gaskets and Seals: Fresh set for leak-free assembly, critical for maintaining pump pressure.
- Hardware Kit: Includes necessary screws, O-rings, and fittings for a secure fit.
- Key Shaft and Backplate: Matches Yamaha tolerances for seamless integration.
Every piece is inspected for quality, so you're not gambling on generics that fail mid-season. This targeted kit focuses on the most failure-prone areas of Yamaha water pumps, extending the life of your lower unit.
Spotting Trouble Early: Signs Your Water Pump Needs Attention
Don't wait for a breakdown. Watch for these red flags during pre-run checks or on the water:
- Slow or erratic water stream from the tell-tale outlet.
- Engine temp gauge climbing unexpectedly.
- Rubber bits in the pee stream—classic impeller shred sign.
- Vibration or noise from the lower unit at idle.
Addressing these promptly prevents costly damage to pistons or heads. A quick impeller swap during annual maintenance is smart insurance, particularly if you're in brackish or salt-heavy waters where debris accelerates wear.
DIY Installation Tips for Smooth Sailing
Most handy boaters tackle this in an afternoon with basic tools: socket set, pliers, gasket scraper, and marine sealant. Drain the gear lube first, remove the lower unit bolts (torque specs matter—check your service manual), then slide off the old pump assembly. Lubricate the new impeller with soapy water for easy keyway alignment, reassemble in reverse, and test on a hose before launch.
Pro Tip: Soak the impeller in hot water briefly to soften it for insertion—makes life easier without twisting.
If you're new to it, pair this with a YouTube visual guide for your model. The result? Crisp water flow and peace of mind.
Why Sierra Over Other Options?
Sierra's reputation in the marine aftermarket shines through with kits that outperform bargain-bin alternatives. They're engineered for Yamaha's exact geometry, balancing cost savings with longevity. Users report 2-3 seasons of solid performance in demanding setups, from bay boats to offshore rigs. It's about value: restore like new without premium pricing.
Frequently Asked Questions
What does the Sierra 18-3429 water pump repair kit include?
It comes with a durable neoprene impeller, wear plate, gaskets, seals, key shaft, backplate, and all necessary hardware for a full Yamaha water pump rebuild.
Is the Sierra 18-3429 compatible with all Yamaha outboards?
This kit fits many popular Yamaha models—consult Sierra's catalog or your engine's service manual to confirm exact fitment for your horsepower and year range.
How do I know when to replace my Yamaha water pump impeller?
Replace annually or every 100-200 hours in saltwater use. Look for weak tell-tale flow, overheating, or rubber chunks in the exhaust stream.
Can I install the Sierra 18-3429 kit myself?
Yes, it's DIY-friendly with standard tools. Remove the lower unit, swap components, and reassemble—about 1-2 hours for experienced mechanics.
What's the difference between Sierra and OEM Yamaha parts?
Sierra offers OEM-equivalent quality at a fraction of the cost, using comparable materials and tolerances trusted by professionals for reliable performance.
How do I maintain the water pump after installation?
Flush with fresh water after every saltwater run, inspect the tell-tale seasonally, and replace the kit proactively to avoid engine damage.
Will this kit improve water flow in an older Yamaha?
Absolutely—fresh components restore optimal pump efficiency, often boosting flow over worn factory parts.
Save $14 when you buy the Sierra 18-3429 3429 Yamaha Water Pump Repair Kit for only $37 from NVN Marine! Same day shipping before 3pm.
Sierra 18-3429 3429 Yamaha Water Pump Repair Kit Technical Specifications
| Type: | |
|---|---|
| Vendor: |
Sierra Engine Parts |
| Weight: |
0.47 lb |
| Description: |
Repair Kit w/o Housing |
| OEM #: |
6H4-W0078-A0-00, 644-W0078-A0-00 |
Sierra 18-3429 3429 Yamaha Water Pump Repair Kit User Reviews
Sierra 18-3429 3429 Yamaha Water Pump Repair Kit Shipping & Return
| Shipping Weight: |
0.47 lb |
|---|---|
| Box Sizes: |
2.00 (h) x 4.00 (w) x 4.00 (l) |
| Cubic Feet: |
32.0 |
| Returnable: |
Yes |
For detailed shipping policy please check our Shipping Policy and you can find our Return and Refund Policy here.



