Water Pump Impeller Replacement for Johnson/Evinrude Outboards – Replaces 375638, 775518
Water Pump Impeller Replacement for Johnson/Evinrude Outboards – Replaces 375638, 775518 is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Replacement for Johnson/Evinrude Outboards – Re...
Water Pump Impeller Replacement for Johnson/Evinrude Outboards – Replaces 375638, 775518 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller is a replacement component for selected Johnson/Evinrude outboard water pump applications. It replaces Johnson/Evinrude reference numbers 375638 and 775518. Confirm the original impeller, engine model, year, and water-pump specifications before ordering.
The impeller is listed in the Sierra catalog as Sierra 18-3002, replacing Johnson/Evinrude numbers 375638 and 775518. Reference numbers are provided for identification and cross-reference purposes; they do not replace model-specific fitment verification.
- Replacement water pump impeller for selected Johnson/Evinrude outboard applications.
- Designed to restore water-pump circulation when the original impeller is worn or damaged.
- Supplied as one impeller unless otherwise stated by the order or packaging.
- Aftermarket replacement component; not an OEM-branded Johnson/Evinrude part.
Part Number Matrix
Use the references below together with your engine model and the original part for identification.
| Brand or Source | Part Number | Reference |
|---|---|---|
| Johnson/Evinrude | 375638 | Replacement reference |
| Johnson/Evinrude | 775518 | Replacement reference |
| Sierra | 18-3002 | Catalog replacement reference for 375638 and 775518 |
Engine & Model Compatibility
This impeller is intended for selected Johnson/Evinrude outboard water-pump applications associated with the reference numbers above. Exact compatibility can vary by engine model, model year, shaft configuration, and water-pump assembly.
Before purchasing, compare the existing impeller and verify all of the following:
- Complete engine brand and model number.
- Model year and any serial-number range shown in the service information.
- Original impeller part number.
- Impeller dimensions, hub style, blade count, and drive-key arrangement.
- Water-pump housing and wear-plate configuration.
| Check | What to Verify | Why It Matters |
|---|---|---|
| Engine identification | Johnson/Evinrude model number and year | Similar horsepower engines may use different water-pump parts. |
| Original reference | 375638 or 775518, or a confirmed equivalent | Part-number matching is the primary identification step. |
| Physical comparison | Outside diameter, height, hub, blades, and keyway | Differences may prevent correct installation or damage the pump. |
| Complete assembly | Housing, wear plate, gasket, key, and water tube alignment | The impeller must operate correctly within the complete water-pump assembly. |
Technical Specs
- Product Type
- Water pump impeller
- Application
- Selected Johnson/Evinrude outboard water-pump applications
- Replacement References
- Johnson/Evinrude 375638 and 775518
- Aftermarket Catalog Reference
- Sierra 18-3002
- Installation
- Direct replacement where the verified application and dimensions match
- Package Quantity
- 1 impeller
What’s in the Box
- 1 x Water pump impeller
Unless specifically stated in the order or packaging, the impeller is supplied without a gasket, wear plate, water-pump housing, or drive key. Reuse or replace related components according to the engine service manual and their condition.
Installation Notes
Follow the service manual for your exact Johnson/Evinrude engine. Water-pump service involves removal of the lower unit and correct alignment of the driveshaft, shift shaft, water tube, impeller, and pump housing.
- Disconnect the battery where applicable, remove the emergency-stop lanyard, and follow the service manual's safety procedures.
- Place the engine in the position specified by the service manual and remove the lower unit fasteners.
- Lower the gearcase carefully while keeping the shift-shaft and water-tube connections in view.
- Remove the water-pump housing and inspect the housing, wear plate, gasket surfaces, drive key, and driveshaft.
- Remove the old impeller and clean debris from the pump components.
- Install the drive key and new impeller in the correct orientation. Do not force the impeller onto the shaft.
- Lubricate or wet the impeller only as permitted by the engine service instructions, then install the pump housing without pinching or folding the blades.
- Reinstall the lower unit, confirming that the driveshaft, shift shaft, and water tube are correctly aligned.
- After assembly, run the engine only in an appropriate water-supply setup and confirm a normal cooling-water discharge.
Maintenance & Troubleshooting
What are the signs of a worn water pump impeller?
Possible signs include weak cooling-water discharge, overheating, steam, an overheating warning, or visible cracking, hardening, melting, or missing blades during inspection. These symptoms can also result from blockages or other cooling-system faults.
How often should the impeller be replaced?
Replace it according to the engine manufacturer's maintenance schedule and inspect it whenever the water-pump assembly is serviced. Frequent operation in saltwater, sand, silt, or shallow water can increase wear.
Does this listing include the drive key or gasket?
No. The package contains one impeller only unless the order or packaging expressly states otherwise. Verify the condition and required part numbers for the key, gasket, wear plate, and housing before beginning installation.
Can I use the reference number alone to confirm fitment?
No. Reference numbers are an important starting point, but model year, serial range, pump design, and physical dimensions must also match. Compare the original part and consult the correct service information for your engine.
Is this an OEM part?
No. This is an aftermarket replacement impeller intended for applications that have been verified against the listed reference numbers and the engine's specifications.
Can I install this myself?
Some owners perform impeller replacement themselves, but lower-unit removal and water-pump assembly require correct procedures and alignment. Use the service manual for your exact engine or have the work performed by a qualified marine technician.
Safety & Important Information
- Verify the engine model, year, original part number, and physical dimensions before ordering.
- Do not operate an outboard without an adequate cooling-water supply.
- Stop testing immediately if the engine overheats or the cooling-water discharge is abnormal.
- Replace damaged gaskets, worn pump components, and a missing or damaged drive key as required by the service manual.
- This is an aftermarket replacement, not an OEM-branded component.
About Sea Sierra
- We supply aftermarket marine replacement parts for maintenance and repair applications.
- Product references are provided to help customers compare replacement components with the original part.
- For the best result, verify application details before installation and follow the engine manufacturer's service procedures.
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