Sierra Engine Parts

Sierra 18-3430 6J8-W0078-A1-00 Yamaha Wp Kit

SKU: 4002648 · UPC: 030999975775 · MPN: 18-3430
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02 · Overview

Sierra 18-3430 6J8-W0078-A1-00 Yamaha Wp Kit — Product description

Revitalize Your Yamaha Outboard with a Reliable Water Pump Kit

Keeping your Yamaha outboard motor running cool under pressure is essential for peak performance on the water. The Sierra water pump kit steps in as a trusted aftermarket solution, designed to restore efficient water flow and prevent overheating issues common in 40-60HP 2-stroke models. Whether you're dealing with impeller wear from extended use or planning a proactive rebuild, this kit delivers the components you need for a smooth, dependable repair.

Built with high-grade materials like durable rubber impellers and precision-machined housings, it mirrors the reliability of original equipment while offering excellent value. Boaters often praise its straightforward fitment, making it a go-to for weekend mechanics and seasoned pros alike.

Perfect Fit for Classic Yamaha Models

This kit aligns seamlessly with a range of Yamaha 2-stroke outboards, including popular 40HP, 48HP, 50HP, and 60HP engines produced in the 1980s and 1990s. Common enduro and standard models like the 40ETLQ, 48ETLU, 50TLRU, and 60TLRU benefit from its exact specifications, ensuring no guesswork during installation. Always cross-check your engine's serial number for the best match, as slight variations exist across production years.

Kit Contents: Everything You Need for a Complete Rebuild

  • Impeller – Flexible neoprene construction for optimal water pickup
  • Key – Ensures secure impeller alignment
  • Outer flange and inner flange – Corrosion-resistant for saltwater exposure
  • Cam follower and liner – Smooth operation with minimal wear
  • Gaskets and O-rings – Fresh seals to prevent leaks
  • Drive pin – Positive engagement for consistent performance

Unlike partial kits, this comprehensive package covers all critical water pump elements, saving you time on sourcing extras.

Why Choose This Kit for Long-Term Outboard Health

A worn water pump can lead to sluggish cooling, higher engine temps, and costly damage down the line. Installing this kit not only restores factory-level water circulation but also enhances fuel efficiency and throttle response. The impeller's aggressive vanes grab water effectively even at idle or trolling speeds, ideal for fishing trips or trailering adventures.

Users report fewer breakdowns after rebuilds, with the kit holding up well in both freshwater and brackish environments. It's a smart upgrade that extends the life of your reliable Yamaha powerhead.

Step-by-Step Installation Insights

Rebuilding your water pump is a manageable DIY job with basic tools like pliers, a screwdriver set, and gear puller. Here's a high-level guide:

  1. Disconnect the lower unit and drain gear lube/flush water.
  2. Remove the water pump housing by unbolting the gearcase.
  3. Extract the old impeller assembly using a puller tool.
  4. Clean mating surfaces thoroughly.
  5. Install new components in reverse order, lubricating O-rings lightly.
  6. Torque bolts to spec and test flush before full assembly.

Pro tip: Winterize by inspecting the pump annually – early detection prevents summer surprises. Pair with fresh gear lube for holistic lower unit care.

Maintenance Tips to Maximize Performance

To get the most from your rebuild:

  • Flush after every saltwater outing to remove salt buildup.
  • Monitor tell-tale stream for steady flow at all RPMs.
  • Avoid dry-running the engine; prime the pump if needed.
  • Replace every 2-3 years or 300 hours, whichever comes first.

These habits keep your Yamaha humming reliably season after season.

Frequently Asked Questions

6J8-W0078-A1-00 Yamaha Wp Kit


SKU: NVN-4002648
MPN: 18-3430
UPC: 030999975775
03 · The numbers

Technical specifications

BrandSierra Engine Parts
ModelSierra 18-3430 6J8-W0078-A1-00 Yamaha Wp Kit
SKU / MFR#4002648

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04 · Before you buy

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05 · Customer voices

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