Description

The Sierra 18-3086 Impeller (AP-007) is a direct replacement raw water pump impeller designed for Yamaha outboards. This impeller is responsible for circulating cooling water through the engine, ensuring proper temperature regulation and preventing overheating.

Manufactured to meet or exceed OEM specifications, this impeller features durable, flexible rubber vanes and a precision-fit hub for reliable performance in both freshwater and saltwater environments.

Ideal for routine maintenance, this impeller restores cooling system efficiency and helps protect your engine from heat-related damage.

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Key Features

• Direct replacement raw water pump impeller
• Flexible rubber vanes for efficient water flow
• Precision-fit hub for secure installation
• Maintains proper engine cooling performance
• Marine-grade construction for long service life
• Sierra limited lifetime warranty

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Engine Compatibility

Yamaha Outboards (2-Stroke)

• 9.9 HP
• 15 HP

Yamaha Outboards (4-Stroke)

• F8
• F9.9
• F15

Tohatsu / Nissan (Yamaha-built models)

• Equivalent small horsepower outboards

Commonly used in portable and small outboard engines

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Serial Number Fitment Notice

Fitment depends on:

• Model year
• Water pump housing type
• Shaft spline configuration

Always confirm using:

• Engine serial number
• OEM part number match

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When This Part Needs Replacement

Replace the impeller if you notice:

• Weak or no telltale stream
• Engine overheating
• Reduced cooling performance
• Cracked, hardened, or missing vanes
• After seasonal storage

Recommended service interval: every 100 hours or annually

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Installation Notes

• Lubricate impeller before installation
• Install vanes in correct rotation direction
• Inspect housing and wear plate
• Ensure proper key alignment on shaft
• Replace gaskets or seals as needed

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Alternate / Superseded Part Numbers

OEM Cross References

• Yamaha: 6G1-44352-00-00
• Yamaha: 6G1-44352-01-00

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Aftermarket Cross References

• Sierra: 18-3086
• Mallory: 9-45602
• GLM: 12020

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Shipping

Shipping: Ships same or next day for fast Canada wide shipping.

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Parts Desk Insight

Small outboard impellers are easy to overlook, but they’re one of the most important maintenance items. Even light use or sitting unused can cause the rubber to stiffen and reduce water flow.

Replacing it regularly keeps your engine running cool and reliable every time you head out