Water Pump Impeller Repair Kit – Fits Mercury Marine 6-15 HP Outboards (Replaces 46-42089A5, 46-42040A5)

Water Pump Impeller Repair Kit – Fits Mercury Marine 6-15 HP Outboards (Replaces 46-42089A5, 46-42040A5)

This water pump impeller repair kit provides a complete solution for servicing the lower unit water pump on a wide range of Mercury and Mariner outboard engines from 1986 to 2005, covering 6 HP to 15 HP models in both 2-stroke and 4-stroke configurations. It also fits select 1998 Force and Sears 9.9-15 HP outboards, ensuring broad compatibility for maintenance and repairs.

As a direct replacement, this kit corresponds to Mercury part numbers 46-42089A5, 46-42089A4, 46-42089A3, and 46-42040A5 / T5, as well as aftermarket parts from Sierra (18-3149) and GLM (12305). All components are manufactured to meet or exceed OEM specifications for reliable performance.

• Engine Fit: Mercury/Mariner 6-15 HP (1986-2005), Force 9.9/15 HP (1998), Sears 9.9/15 HP (1998)
• Installation: Direct-fit replacement for the lower unit water pump assembly.
• Contents: Includes impeller, housing, face plate, gaskets, seals, and all necessary hardware for a complete overhaul.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

For Force and Sears models, confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Water pump impeller (47-42038Q02/420382/47-42038-2)
• 1 x Impeller Key
• 1 x Housing assembly (42089A2)
• 1 x Face Plate (42200)
• 1 x Gasket (19202/192043)
• 1 x Water pump base assembly (42040T5)
• 2 x Oil seal (413651)
• 2 x Washers
• 1 x Quad ring (822236)
• 1 x Screw

Installation Guide

1. Prepare the Outboard: Disconnect the battery and shift the outboard into the neutral position.
2. Access the Lower Unit: Remove the propeller and drain the gearcase oil completely.
3. Remove Gearcase: Unbolt and carefully lower the gearcase assembly from the driveshaft housing.
4. Disassemble Old Pump: Locate and unscrew the bolts securing the old water pump housing. Remove the housing to expose the impeller.
5. Remove Old Components: Take out the old impeller, impeller key, and wear plate. Note their orientation.
6. Clean Surfaces: Thoroughly clean all mounting surfaces, removing any old gasket material or debris.
7. Install New Gaskets & Plate: Place the new gaskets and face plate onto the gearcase.
8. Install New Impeller: Slide the new impeller key onto the driveshaft and push the new impeller down into the housing while turning the driveshaft clockwise to bend the vanes correctly.
9. Reassemble Pump: Install the new housing assembly over the impeller and tighten the bolts to the manufacturer's specified torque.
10. Reinstall Lower Unit: Carefully guide the gearcase back into position, ensuring the driveshaft, shift shaft, and water tube are properly aligned. Secure with bolts.
11. Final Steps: Refill the gearcase with fresh marine gear lube and reinstall the propeller.
12. Test Operation: Start the engine using a water supply (flushing attachment or in water) and check for a steady "telltale" water stream, indicating proper pump function.

Troubleshooting & FAQ

How do I confirm this kit fits my Mercury motor?

Always check your engine's serial number against the ranges provided in the compatibility table. This kit is designed for specific 6-15 HP models from 1986 onward (e.g., SN 0A197112 and up for 6, 8, and 9.9 HP 2-Strokes). If your serial number is not listed, this kit may not fit.

What are the signs my water pump impeller is failing?

Common symptoms include the engine overheating, especially at low speeds, and a weak or non-existent water stream from the "telltale" indicator outlet. Upon inspection, a worn impeller may be brittle, have cracks, or show signs of melted rubber.

How often should I replace the water pump impeller?

For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or 100-200 hours of use. Replacement frequency should be increased if the outboard is operated primarily in saltwater or sandy/silty conditions.

OEM vs. Aftermarket?

This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?

We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?

This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.