Water Pump Impeller with Key – Yamaha 2-Stroke 4A/4B/5C & 4-Stroke F4A/F4B/F5A/F6C; Mercury Mariner 4A/5C

Product Details

This Water Pump Impeller with Key is an aftermarket replacement for selected Yamaha and Mercury Mariner outboard cooling systems. It is supplied as an impeller-and-key package and is intended to restore water-pump circulation when the original impeller is worn, cracked, deformed, or damaged.

The company fitment records identify this SKU for Yamaha 2-stroke models 4A, 4B, and 5C; Yamaha 4-stroke models F4A, F4B, F5A, and F6C; and Mercury Mariner 2-stroke models 4A and 5C. Verify the complete engine model and the part number installed in your engine before ordering.

The primary Yamaha reference is 6E0-44352-00, also commonly written in catalog format as 6E0-44352-00-00. Related aftermarket references listed for this product include Sierra Marine 18-3073, Mallory Marine 9-45611, and GLM Marine 89860. Mercury Mariner reference 47-96305M is also listed for the corresponding 2-stroke application.

• Aftermarket water pump impeller replacement
• Includes one matching installation key/pin
• Designed for the listed Yamaha and Mercury Mariner applications
• Use the original part and engine identification to confirm fit before installation

Part Number Matrix

These are reference numbers associated with this SKU. Part-number matches should be confirmed against the engine model and cooling-system configuration.

Engine & Model Compatibility

The applications below are the model designations recorded for this SKU. Model-year, serial-number, shaft-length, and lower-unit configuration information is not specified in the company record, so confirm those details before purchase.

Technical Information

• Product type: Water pump impeller
• Construction: Rubber impeller with drive key/pin
• Package configuration: One impeller and one key/pin
• Primary Yamaha reference: 6E0-44352-00

Exact blade count, impeller height, and other dimensional specifications are not stated in the company record for this SKU. Do not use dimensions from a different impeller variant as a substitute for model and part-number verification.

What's in the Box

• One aftermarket water pump impeller
• One matching impeller key/pin

Water-pump housing, wear plate, gasket, O-rings, bolts, and other service parts are not included unless separately stated. The key/pin is included with this SKU even though some impeller component catalogs list the key separately.

Installation Notes

1. Identify the engine model and confirm that the existing impeller matches one of the references listed above.
2. Stop the engine, disconnect the battery where applicable, remove the engine cover, and follow the manufacturer's service procedure for accessing the water pump.
3. Remove the water-pump housing and keep track of the original fasteners and sealing components.
4. Remove the old impeller and inspect the housing, wear plate, gasket surfaces, driveshaft, and keyway for damage or corrosion.
5. Remove all broken rubber fragments and debris from the pump chamber and cooling passages that may have been affected.
6. Install the supplied key/pin fully into the driveshaft keyway before fitting the impeller.
7. Lubricate the impeller with clean water, glycerin, or a lubricant approved for marine rubber components. Do not use petroleum-based products.
8. Fit the impeller over the key/pin and rotate it in the correct driveshaft direction while lowering the pump housing into position.
9. Replace worn gaskets and O-rings as required. Reinstall the housing and tighten fasteners according to the engine manufacturer's specifications.
10. Reassemble the lower unit according to the service manual, then run the engine only with an adequate water supply.
11. Verify a steady cooling-water discharge and monitor the engine for overheating or leaks before returning it to service.

Troubleshooting & FAQ

How do I know when to replace my impeller?

Replace the impeller when it has cracked, taken a permanent set, lost or damaged vanes, or when cooling-water flow is weak or absent. Overheating, an abnormal temperature increase, or a damaged impeller found during service are also reasons to replace it. Follow the maintenance interval in the engine manufacturer's service documentation.

Will this impeller fit my specific engine?

This SKU is recorded for Yamaha 2-stroke 4A, 4B, and 5C models; Yamaha 4-stroke F4A, F4B, F5A, and F6C models; and Mercury Mariner 2-stroke 4A and 5C models. Confirm the complete model designation and compare the existing impeller or part number before ordering.

Is the key or pin included?

Yes. The company package statement specifies that this product includes one matching impeller key/pin.

Can I reuse the old gasket or O-rings?

Inspect all gaskets and O-rings during service. Replace any seal that is damaged, hardened, flattened, or otherwise unable to provide a reliable seal. This listing contains the impeller and key/pin only; replacement seals are not included.

Why is the engine still overheating after impeller replacement?

Check for blocked cooling passages, damaged pump housing or wear plate, an incorrectly installed key/pin, damaged impeller vanes, a blocked tell-tale, a thermostat problem, or an inadequate water supply during testing. If overheating continues, stop the engine and follow the manufacturer's diagnostic procedure.

What lubricant should I use on the impeller?

Use clean water, glycerin, or a lubricant specifically approved for marine rubber components. Avoid petroleum-based lubricants because they may damage the impeller material.

Is this an OEM part?

No. This listing is for an aftermarket replacement. Yamaha, Mercury, Sierra Marine, Mallory Marine, and GLM Marine numbers are used only as reference numbers for identification and compatibility.

Safety & Important Information

• Verify the complete engine model, stroke, and existing impeller number before ordering.
• Do not rely on horsepower alone to determine fitment.
• Do not operate an outboard without an adequate water supply.
• Inspect the water-pump housing, wear plate, gaskets, O-rings, and cooling passages during installation.
• Professional installation is recommended when lower-unit or water-pump service procedures are unfamiliar.
• This is an aftermarket replacement, not an OEM component.

About Sea Sierra

• We supply aftermarket marine replacement parts identified by verified reference numbers and application information.
• Each product page is prepared to help customers compare model designations, part numbers, and package contents before ordering.
• For the best fitment result, always compare the original component and consult the engine service information.