Water Pump Impeller Repair Kit – Fits Mercury Marine 30 JET, 35-70 HP Outboards (Replaces 46-77177A3, 46-77516A3, 46-73640A2)

Water Pump Impeller Repair Kit – Fits Mercury Marine 30 JET, 35–70 HP Outboards

This water pump impeller repair kit is designed for Mercury Marine/Mariner 2-Stroke 30 JET, 35–70 HP outboard motors, covering various models manufactured between 1976 and 1997. Please refer to the compatible engine model list below to confirm your specific application using the serial number range.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, providing a complete solution for servicing or rebuilding your outboard's water pump.

• Includes all necessary components for a full replacement: impeller, upper and lower housings, wear plates, gaskets, seals, and O-rings.
• Engineered with durable materials: Marine Grade CR-Neoprene impeller, Nylon PA66 housing, and a Stainless Steel 316 wear plate for corrosion resistance and longevity.
• Installs in the lower unit gearcase to restore cooling system performance.

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.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (47-89983/18-3007)
• 1 x Upper Pump Housing (46-77822A1/18-3118)
• 1 x Water Pump Base (46-77177A1)
• 2 x Plates (27-32770, 27-19551)
• 2 x Drain Gaskets (12-20260, 12-19183)
• 1 x Drain Plug (12-49221)
• 3 x Water Pump Base Gaskets (27-32771, 27-77417, 27-19552)
• 3 x O-Rings (25-26855, 25-45711, 25-26722)
• 1 x Installation Instructions

Installation Guide

For detailed instructions, always refer to your outboard's official service manual. The following is a general guide to the installation process.

1. Safety First: Disconnect the battery and remove the spark plug wires. Shift the outboard into the neutral position.
2. Drop the Lower Unit: Remove the bolts securing the lower unit (gearcase) to the upper leg of the outboard. Carefully lower it to gain access to the water pump.
3. Disassemble the Pump: Unbolt and remove the water pump housing. You may need to gently pry it loose.
4. Remove Old Components: Take note of the order of components. Remove the old impeller, wear plate, gaskets, and seals.
5. Clean and Prepare: Thoroughly clean the driveshaft and all mating surfaces on the housing and base.
6. Install New Components: Install the new base gasket and wear plate. Slide the new impeller onto the driveshaft, turning the shaft clockwise to bend the vanes correctly.
7. Install New Housing: Apply a light coat of marine grease to the inside of the new housing and install it over the impeller, along with any new gaskets or seals.
8. Reassemble: Bolt down the new housing to the specified torque. Reattach the lower unit to the outboard, ensuring the driveshaft and water tube are properly aligned.
9. Final Checks: Reconnect the battery and spark plug wires. Before starting, ensure a steady stream of water exits the tell-tale port.

Note: Owners of Japanese-made outboards may need to retain the original housing grommet seal gasket. Non-Japanese outboards may require a separate gasket kit (26-38452/26-38453).

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific engine?
A: The best way is to match your engine's serial number to the ranges listed in the compatibility table above. The serial number is typically found on a plate on the transom bracket. Using the Mercury Serial Number Guide linked above can help you pinpoint your model and year.

Q: Are there any special considerations for installation?
A: Yes. If you have a Japanese-made Mercury/Mariner outboard, it is recommended to retain the original housing grommet seal gasket. For other models, a separate grommet seal gasket kit (part no. 26-38452/26-38453) may be necessary.

Q: What are the signs that my water pump impeller needs replacement?
A: Common signs of a failing impeller include a weak or non-existent water stream from the tell-tale (pee hole), engine overheating alarms, and in some cases, a reduction in engine performance. Visible damage like cracked, brittle, or missing vanes on the old impeller also indicates a need for replacement.

Q: How often should I replace the water pump impeller?
A: As a general rule of thumb, it is recommended to inspect and/or replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. This interval can vary based on usage conditions (e.g., saltwater vs. freshwater, sandy/silty water).

Q: OEM vs. Aftermarket?
A: 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.

Q: How fast do you ship and how much does it cost?
A: 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.

Q: What is your warranty and return policy?
A: 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.