Water Pump Impeller Repair Kit – Fits Mercury/Mariner Outboards 65-225 HP & MerCruiser Alpha One Gen I (Replaces 96148Q8, 96148A8)

Product Details

This Water Pump Impeller Repair Kit is an essential service component for maintaining the cooling system on a wide range of Mercury/Mariner outboards and MerCruiser stern drives. It is designed for 2-stroke Mercury/Mariner outboards from 65-225 HP (4-cylinder through V6 models, 1970s–1990s) and MerCruiser I, R, MR, and Alpha One Gen I drives (S/N 2495186 through 0D469858).

This kit serves as a direct replacement for multiple part numbers, including Mercury 46-96148Q8, 96148A8, 96148A5, Sierra 18-3517, and Mallory 9-48311, ensuring broad compatibility for engines using short vane impellers.

• Installs in the lower unit (outdrive) to restore cooling performance.
• Features a durable plastic housing designed for high flow rates.
• Includes the essential impeller, housing, and face plate for a complete rebuild.

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 and Mariner outboards, this kit fits various 2-stroke models from 65 HP to 225 HP. Please verify your specific model and year range.

For MerCruiser stern drives, this kit applies to legacy models including I, R, MR, and Alpha One Gen I units up to 1990 with specific serial number ranges.

Technical Specs

Product Type

Water Pump Impeller Repair Kit

Installation

Lower Unit / Outdrive

Housing Material

Plastic

Housing Color

Black

Weight

0.37 kg (0.82 lb)

Other Technical Attributes

Designed for higher flow rates and improved cooling

What’s in the Box

• 1 x Water Pump Impeller (89984T4)
• 1 x Plastic Pump Housing (96148A1)
• 1 x Face Plate (8M0204677)

Installation Notes

1. Disconnect the battery and remove the spark plug leads for safety.
2. Place the outboard or stern drive in a suitable position to access the lower unit.
3. Drain the gearcase lubricant by removing the fill and vent plugs.
4. Remove the propeller assembly.
5. Loosen and remove the bolts securing the lower unit (gearcase) to the midsection.
6. Carefully separate the lower unit. Be mindful of the shift shaft linkage.
7. Unbolt and remove the old water pump housing assembly. Note the orientation of all parts.
8. Clean the mounting surfaces and inspect the driveshaft for wear or damage.
9. Assemble the new kit components in the reverse order of disassembly. Lightly grease the new impeller.
10. Reinstall the lower unit, ensuring the water tube and shift shaft are correctly aligned.
11. Torque all bolts to manufacturer specifications, refill the gear lube, and reinstall the propeller.
12. Start the engine and verify water is exiting the tell-tale port, indicating a successful installation.

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.