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

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

This water pump impeller repair kit is designed for a wide range of Mercury/Mercruiser applications, including 4-cylinder and V6 outboard engines from 65HP to 220HP (2-Stroke) and Pre-Alpha/Alpha One stern drives manufactured between 1970 and 1990.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility for restoring your engine's cooling system performance.

• Engine compatibility: 65–220HP 2-Stroke outboards and Alpha One/Pre-Alpha stern drives.
• Installation type: Direct replacement for original equipment.
• Key components: Includes plastic upper housing assembly and a short-vane impeller.

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 Stern Drives

Technical Specifications

Package Contents

• 1 x Water Pump Housing Assembly (Plastic)
• 1 x Impeller
• 1 x Face Plate
• 1 x Water Tube Guide Sleeve
• 1 x Drive Key/Pin
• Gaskets
• O-rings
• Gearlube Fill & Vent Screw Seals
• Note: Base not included

Installation Guide

1. Safety First: Disconnect the battery cables to prevent accidental starting.
2. Drain Gear Lube: Place a drain pan under the lower unit and remove the upper and lower gear lube drain screws. Allow all oil to drain.
3. Remove Lower Unit: Remove the bolts securing the lower unit (gearcase) to the engine's midsection. Carefully lower the unit away from the engine.
4. Disassemble Old Pump: Locate the water pump on top of the gearcase. Remove the bolts securing the pump housing, then lift off the housing and remove the old impeller, gaskets, and wear plate.
5. Clean and Inspect: Thoroughly clean the mounting surfaces, removing any old gasket material or debris.
6. Install New Components: Place the new gaskets, wear plate, and drive key. Slide the new impeller onto the driveshaft, turning the shaft clockwise to ease installation of the vanes.
7. Install New Housing: Apply a light coat of marine grease to the inside of the new housing and install it over the impeller. Secure with the bolts, tightening them to the manufacturer's specified torque.
8. Reinstall Lower Unit: Carefully guide the lower unit back into place, ensuring the driveshaft, shift shaft, and water tube align correctly. Reinstall and tighten the mounting bolts.
9. Refill Gear Lube: Pump fresh marine gear lube into the lower drain hole until it seeps out of the upper vent hole. Reinstall both drain screws with new seals.
10. Test Operation: Reconnect the battery. Start the engine using a water source (flushing muffs) and verify a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this fits my Mercruiser Alpha One?
Check your stern drive's serial number. This kit is designed for Pre-Alpha drives (1970-1983) and Alpha One drives (1983-1990) with serial numbers ranging from 2495186 to 0D469858.

What are the signs my water pump impeller needs replacing?
Common signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "telltale" outlet, and a cracked, stiff, or brittle appearance on the old impeller's vanes upon inspection.

Does this kit include the lower base?
No, this kit is an upper housing repair kit. It includes the upper plastic housing, impeller, face plate, gaskets, and seals. The water pump base is not included and must be purchased separately if needed.

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.