Water Pump Impeller Kit – Fits Mercury/Mercruiser Alpha One & Outboard Motors (Replaces 46-96148A8, 96148Q8)

Product Details

This Water Pump Impeller Kit provides a complete solution for servicing the cooling systems on Mercury/Mercruiser engines. It is designed for Alpha One sterndrive units (1983–1990) and a wide range of Mercury outboard motors from 65 to 220 HP that utilize short-vane impellers, ensuring your engine maintains optimal operating temperature.

The kit serves as a direct interchange for Mercury part numbers 46-96148A8, 96148Q8, 46-96148T8, and several others, providing a reliable aftermarket alternative for routine maintenance or repair.

• Engineered as a direct replacement for Mercury/Mercruiser systems.
• Constructed with a durable Nylon PA66 plastic housing and a neoprene rubber impeller.
• Includes all necessary gaskets, seals, and hardware for a complete installation.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury Outboards, this kit fits various 4-cylinder and V6 models. Please verify your engine's serial number falls within the specified range for your model and horsepower.

For MerCruiser Stern Drives, this part is compatible with Pre-Alpha, Alpha One, I, R, and MR models. Serial number ranges are the most reliable way to confirm fitment.

For Johnson/Evinrude applications, this kit is listed as an alternate fitment for select models. Please verify your requirements independently as OEM cross-references are not provided.

Technical Specs

Product Type

Water Pump Impeller Kit

Installation

Direct Replacement for Mercury/Mercruiser systems

Housing Material

Nylon PA66 Plastic (Water Pump Housing)

Impeller Material

Neoprene Rubber

Base Size

2.356 inches (59.8 mm)

Weight

330 grams (0.73 lbs)

Compatible With

Mercury Marine outboard motors and Mercruiser Alpha One stern drives

Serial Number Range

2491586 through 0D469858 (for Mercruiser applications)

Warranty

90 days (as stated by some retailers)

What’s in the Box

• 1 x Water Pump Impeller
• 1 x Upper Pump Housing
• 1 x Face Plate
• 1 x Drive Key (Pin)
• 1 x Face Seal
• 1 x Seal Carrier
• 1 x Water Tube Coupling
• 1 x Set of Gaskets
• 1 x Set of O-Rings
• 2 x Gearlube Fill & Vent Screw Seals

Installation Notes

1. Disconnect the battery to prevent accidental starting.
2. Access the lower unit of the outboard or sterndrive. You may need to shift into forward gear to disconnect the shift shaft.
3. Remove the lower unit from the engine by unbolting it.
4. Locate and unbolt the water pump housing assembly.
5. Remove the old impeller, housing, wear plate, and gaskets. Note the orientation of the impeller vanes.
6. Thoroughly clean all mating surfaces, removing any old gasket material or debris.
7. Install the new gaskets, wear plate, and drive key.
8. Lubricate the new impeller and housing with a marine-grade lubricant. Install the impeller by turning the driveshaft clockwise to bend the vanes correctly.
9. Install the new housing, seals, and hardware, torquing bolts to manufacturer specifications.
10. Reinstall the lower unit, ensuring the water tube, driveshaft, and shift shaft are properly aligned.
11. Once reassembled, start the engine using a water supply (flushing muffs) and check for a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

Safety & Important Info

• Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.