Sierra Engine Parts

Sierra 18-3381 393509 Johnson/Evinrude Water Pump Kit

SKU: 4002636 · UPC: 030999753588 · MPN: 18-3381
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02 · Overview

Sierra 18-3381 393509 Johnson/Evinrude Water Pump Kit — Product description

Keep your Johnson or Evinrude outboard running cool and efficient with this reliable water pump kit. Designed as a direct replacement for OEM components, it ensures optimal coolant flow to prevent overheating during long days on the water. Boaters trust this kit for its durable construction and straightforward installation, making it a go-to choice for routine maintenance or emergency repairs.

Key Features of the Sierra Water Pump Kit

  • Precision-Machined Impeller: Delivers consistent water pressure and volume, matching factory specs for seamless performance.
  • Corrosion-Resistant Housing: Built from high-grade materials that withstand saltwater exposure and harsh marine environments.
  • Complete Kit Contents: Includes impeller, wear plate, gaskets, seals, and O-rings—everything needed for a full rebuild without hunting for extras.
  • Easy Bolt-On Fit: Engineered to align perfectly with Johnson/Evinrude mounting points, minimizing downtime.
  • Replaces OEM 393509: A cost-effective alternative that meets or exceeds original equipment standards.

Why This Water Pump Kit Stands Out for Outboard Owners

Overheating is every boater's nightmare, leading to warped heads, seized pistons, or complete engine failure. This kit tackles that risk head-on by restoring full cooling capacity. Unlike worn factory pumps that lose efficiency over time, the fresh impeller spins freely to push water through the cooling passages effectively. It's especially vital for V4 and V6 models where heat buildup happens fast under load.

Sierra's engineering focuses on longevity—think thicker vanes on the impeller that resist deformation and a wear plate that extends service life. Regular replacement every 2-3 years or 300 hours of use keeps your engine humming, avoiding those mid-trip breakdowns that ruin fishing trips or family outings.

Installation Tips for a Flawless Swap

Swapping out your old water pump doesn't require a marine mechanic's expertise. Start by flushing the cooling system to remove debris. Drain the gear case oil if accessing from below. Use a puller tool for the old impeller to avoid damage, then lube the new one generously with marine grease before sliding it on. Torque bolts to spec, and test-run in a barrel before hitting open water. Most jobs take under an hour with basic tools.

"Pro Tip: Always inspect the lower unit gears while the pump is off—catch wear early to save bigger headaches later."

Boosting Engine Reliability with Proper Maintenance

A top-notch water pump is just one piece of the puzzle. Pair it with fresh gear lube, annual lower unit inspections, and monitoring tell-tale flow. In murky or weedy waters, clean the intake screen weekly to prevent clogs. This holistic approach maximizes your outboard's lifespan and keeps fuel efficiency high.

Frequently Asked Questions

Equip your Johnson or Evinrude with this proven water pump kit and fish harder, longer. Reliable cooling means more time enjoying the water, less worrying about the engine.

393509 Johnson/Evinrude Water Pump Kit


SKU: NVN-4002636
MPN: 18-3381
UPC: 030999753588
03 · The numbers

Technical specifications

BrandSierra Engine Parts
ModelSierra 18-3381 393509 Johnson/Evinrude Water Pump Kit
SKU / MFR#4002636

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04 · Before you buy

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05 · Customer voices

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