Description

The Sierra 18-8926 Raw Water Pump Impeller is a high-quality replacement impeller designed to maintain proper seawater flow in marine cooling systems. This impeller is a critical component responsible for drawing water through the engine to regulate operating temperature and prevent overheating.

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

Ideal for routine maintenance or replacing worn or damaged impellers, the 18-8926 helps restore full cooling system efficiency and protects 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 durability
• Sierra limited lifetime warranty

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Engine Compatibility

Volvo Penta

• AQ Series engines
• Small block V6 / V8 applications
• Select sterndrive and inboard setups

OMC / Cobra / Stringer

• GM-based V6 and V8 engines

Crusader / PCM / Inboard Engines

• 4.3L, 5.0L, 5.7L, 7.4L, 8.1L (verify application)

Fits engines equipped with compatible engine-mounted or crank-driven raw water pumps.

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Serial Number Fitment Notice

Fitment depends on:

• Exact pump model
• Shaft size and spline configuration
• Engine manufacturer and year

Always confirm using:

• Pump model or casting number
• OEM part number match (18-8926 cross reference)

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When This Part Needs Replacement

Replace the impeller if you notice:

• Reduced or no water flow
• Engine overheating
• Cracked, missing, or hardened impeller vanes
• Reduced cooling at higher RPM
• After seasonal storage

Recommended service interval: every 100 hours or annually

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Installation Notes

• Lubricate impeller before installation
• Install with correct vane rotation
• Inspect pump housing and wear plate
• Replace gasket or O-ring as required
• Check for debris from old impeller in system

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Alternate / Superseded Part Numbers

OEM Cross References

• Volvo Penta: 875583, 3858256
• OMC: 0986397

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Aftermarket Cross References

• Johnson Pump: 09-812B
• Jabsco: 1210-0001

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Shipping

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

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Parts Desk Insight

Impellers often fail gradually—still moving water at idle but not enough at higher speeds. Replacing yours on schedule helps avoid overheating when you’re out on the water and need full engine performance