Water Pump Impeller Kit – Fits Mercury/Mariner 65-220HP & MerCruiser Alpha One (Replaces 46-96148A8, 46-96148Q8, 46-96148T8)

Water Pump Impeller Kit – Fits Mercury/Mariner 65-220HP & MerCruiser Alpha One (Replaces 46-96148A8, 46-96148Q8, 46-96148T8)

This water pump impeller repair kit provides the necessary components for servicing and restoring the cooling system on a wide range of Mercury/Mariner outboards and MerCruiser sterndrives. It is designed for 2-stroke, 4-cylinder through V6 models from 65 to 220 HP with short-vane impellers, as well as Pre-Alpha, Alpha One, MC-1, R, and MR sterndrive models within specific serial number ranges.

This kit is a direct replacement for Mercury part numbers 46-96148A8, 46-96148Q8, and 46-96148T8. It also replaces aftermarket parts such as Sierra 18-3217 and 18-3316 (kit with housing), and Quicksilver 96148Q8.

• Installation Type: Direct replacement for a seamless fit.
• Core Components: Includes the neoprene impeller, plastic housing, wear plate, and all required gaskets and seals for a complete overhaul.
• Engine Compatibility: Fits various Mercury/Mariner outboards (65-220HP) and MerCruiser sterndrives (Pre-Alpha, Alpha One, R/MR/MC-1).

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.

Mercury/Mariner Outboards

MerCruiser Sterndrives

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (47-89984T4)
• 1 x Pump Housing Assembly (46-96148A1)
• 1 x Wear Plate (32435)
• 1 x Water Tube Gasket (23-29804)
• 1 x Grommet (26-38970)
• 1 x Face Seal (26-45577)
• 7 x Gaskets (27-42631-1, 26-20260, 12-19183, 27-85610-1, 27-85608-1, 27-85609-1, 27-32438)

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is completely off before starting.
2. Access the Pump: Locate and remove the lower unit (gearcase) from the outboard or sterndrive.
3. Remove Old Housing: Unbolt and carefully remove the existing water pump housing. Take note of how the components are assembled.
4. Extract Old Parts: Remove the old impeller, key, wear plate, and any gaskets. The impeller may be stuck, requiring gentle prying.
5. Clean Surfaces: Thoroughly clean all mating surfaces on the lower unit and housing, removing any old gasket residue to ensure a perfect seal.
6. Install New Components: Place the new gaskets and wear plate into position.
7. Install Impeller: Slide the new impeller key onto the drive shaft. Push the new impeller onto the shaft while turning the shaft clockwise to set the vanes in the correct direction.
8. Grease and Install Housing: Apply a light coat of marine grease to the inside of the new housing, then slide it down over the impeller.
9. Secure Housing: Align the housing and tighten the bolts to the manufacturer's specified torque.
10. Reassemble: Re-install the lower unit onto the leg.
11. Test Operation: Reconnect the battery. Start the engine using a water supply (flushing muffs) and check for a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this impeller kit fits my engine?
This kit is designed for Mercury/Mariner 65-220HP outboards and MerCruiser Pre-Alpha/Alpha One sterndrives. Please check the "Compatible Engine Models" table and verify your engine's serial number falls within the specified ranges. Cross-reference your existing part number with those listed in the "Part Number Cross-Reference" table for confirmation.

What are common signs that my water pump impeller needs replacement?
Common signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "telltale" outlet, and a brittle, cracked, or deformed appearance of the old impeller upon inspection.

How often should the water pump impeller be replaced?
As a preventative maintenance item, it is generally recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of use, depending on operating conditions (e.g., saltwater vs. freshwater).

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.