Water Pump Impeller for OMC Cobra King (1992–1995) – Replaces 987176, 3854072, 18-30585

Product Details

This water pump impeller is an aftermarket replacement for OMC Cobra King marine engines. It is listed for King Cobra applications from 1992–1995 and is intended to restore water-pump circulation and help maintain proper engine cooling.

The impeller is supplied as a single replacement component and is identified by the manufacturer reference Sierra Marine 18-30585. It replaces the listed OMC references 987176, 0987176, 3854072, and 03854072.

• Replacement impeller for OMC Cobra King water pump assemblies
• Single impeller supplied; no gasket, key, housing, wear plate, or water-pump kit is included
• Suitable for listed 2-stroke and 4-stroke water-pump impeller applications where the reference numbers and engine application match
• Designed to support dependable cooling-water circulation in compatible marine engines

Part Number Matrix

Use the following references to compare the replacement impeller with the part being removed. Number matching alone does not replace verification of the complete engine application.

Engine & Model Compatibility

The company application is listed as OMC Cobra King all models. The Sierra application catalog specifically identifies this impeller as fitting King Cobra models from 1992–1995. Confirm the engine or stern-drive identification and existing impeller number before ordering.

Technical Specs

Part Type

Water Pump Impeller

Product Form

Single impeller, not a kit

Application

OMC Cobra King marine engine or stern-drive cooling system

Listed Engine Types

2-stroke and 4-stroke water-pump impeller applications

Primary Application Range

King Cobra, 1992–1995

OEM References

987176, 0987176, 3854072, 03854072

Aftermarket Reference

Sierra Marine 18-30585

What's in the Box

• Water pump impeller × 1

Gaskets, keys, seals, housings, wear plates, and other water-pump components are not included unless separately stated.

Installation Notes

1. Disconnect the battery or power source and allow the engine to cool completely before beginning work.
2. Follow the engine or stern-drive service manual to remove the lower unit or water-pump housing and access the existing impeller.
3. Remove the old impeller and note the direction of vane curvature before installation.
4. Inspect the impeller housing, wear plate, key, seals, and related components for scoring, corrosion, cracking, or damage. Replace damaged parts as required.
5. Lubricate the impeller with glycerin, soapy water, or a lubricant approved for rubber impellers. Do not use petroleum-based grease or oil.
6. Install the impeller with the vanes oriented for the correct direction of rotation and ensure the drive key is properly positioned.
7. Reassemble the water-pump housing and lower unit or stern-drive components according to the service manual and manufacturer torque specifications.
8. Run the engine only with an appropriate water supply and verify normal cooling-water flow before returning the vessel to service.

Troubleshooting & FAQ

How do I know if my impeller needs replacing?

Common symptoms include reduced or absent cooling-water flow, engine overheating, a weak tell-tale stream where applicable, or cracked, hardened, or missing impeller vanes during inspection. Replace the impeller according to the engine manufacturer's maintenance schedule and operating conditions.

Will this fit every OMC Cobra model?

The company application identifies OMC Cobra King all models, while the referenced Sierra application specifically identifies King Cobra models from 1992–1995. Verify the engine or drive year, model, existing impeller, and one of the listed reference numbers before purchase.

Is this a complete water-pump kit?

No. This listing is for one replacement impeller only. It does not include a key, gasket, seal, housing, wear plate, or other water-pump parts.

Can I install the impeller myself?

Installation may be suitable for an experienced boat owner with the correct tools and service information. Follow the manufacturer's service procedure carefully, particularly for vane orientation, key placement, sealing surfaces, and fastener torque. Use a qualified marine technician if you are unsure.

What lubricant should I use during installation?

Use glycerin, a mild dish-soap solution, or a lubricant specifically approved for rubber water-pump impellers. Avoid petroleum-based grease and oil because they may damage the impeller material.

Is this an OEM part?

No. This is an aftermarket replacement impeller. Sierra Marine 18-30585 and the OMC numbers shown in the part-number matrix are reference numbers used to identify the intended application.

Safety & Important Information

• Confirm the complete engine or stern-drive application and compare the original impeller before ordering.
• Do not operate the engine without an adequate water supply.
• Inspect related water-pump components during installation and replace any damaged parts.
• This is an aftermarket replacement component, not an OEM-manufactured part.
• Professional marine service is recommended when application, installation, or service-manual requirements are uncertain.

About Sea Sierra

• Marine Replacement Parts — Replacement components for selected marine engine and drive applications.
• Application-Focused Listings — Reference numbers and model information are provided to help customers compare compatible parts.
• Replacement Value — Aftermarket alternatives for routine marine maintenance and repair needs.