GHmarine Water Pump Kit for MerCruiser Alpha 1 Gen 1 Sterndrive — Complete Rebuild Kit with Impeller & Housing

GHmarine 96148A8 is a full replacement water pump kit designed to restore cooling flow for MerCruiser Alpha 1 Gen 1 (MR/Alpha One) sterndrives.

If your MerCruiser Alpha One Gen 1 sterndrive is showing signs of reduced cooling or you’re doing scheduled maintenance, this GHmarine kit supplies the impeller, housing, gaskets and seals needed for a full water pump rebuild. The kit matches common OEM and aftermarket part numbers and includes the base and face components to fit units with serial numbers in the range noted by the manufacturer.

Will this GHmarine kit fit my MerCruiser Alpha 1 Gen 1 sterndrive?

Compatibility targets MerCruiser MR/Alpha One Gen 1 sterndrives and units with the specified serial number range. Always confirm the base diameter and part references before ordering to ensure a correct fit.

• Fits Mercury MerCruiser MR/Alpha One Gen 1 sterndrives (complete kit with base & housing).
• Cross-references: Sierra 18-3320, GLM 12120, OEM 46-96148A8, and related numbers.
• Base diameter: 2.356 inches — verify your existing base measurement.
• Recommended: compare your drive's serial number range and base part number before purchase.

What parts are included in the water pump kit?

This GHmarine package supplies all primary components needed to rebuild the pump assembly so you can replace worn parts in one service session. Components are provided to match typical OEM configurations for a full rebuild.

• Impeller molded for proper water flow and fit.
• Pump housing and face plate to restore casing integrity.
• Gaskets, face seal, seal carrier and drive key for a leak-free assembly.
• Water tube coupling and additional hardware shown in product images.

How does installing this kit improve my sterndrive performance?

Replacing a worn impeller and deteriorated seals restores proper cooling circulation and reduces overheating risk caused by reduced flow. Fresh gaskets and the correct housing help prevent leaks and extend the life of the pump assembly.

• New impeller renews water flow and pressure through the engine cooling circuit.
• Replaced seals and gaskets prevent external leaks and internal bypassing.
• Correctly matched housing and base ensure proper alignment and longevity.
• Drive key and coupling maintain secure connection to the engine drive shaft.

How should I prepare for installation and what should I check afterward?

Gather basic hand tools and a service manual for your MerCruiser model, and have a torque wrench for correct fastener settings. After installation, run the engine and confirm steady raw-water flow at the telltale or cooling outlets and inspect for leaks.

• Tools: screwdrivers, pliers, gasket scraper, torque wrench, and marine grease.
• Pre-check: verify base diameter (2.356 in) and serial number compatibility.
• Post-check: run engine, watch flow from the telltale, and inspect for weeping seals.
• Tip: replace impeller on schedule and keep a spare impeller aboard for emergencies.

Who is this for: The GHmarine 96148A8 water pump kit is intended for boat owners, mechanics and DIYers working on MerCruiser Alpha 1 Gen 1/MR sterndrives who need a complete replacement pump assembly. It’s suitable for routine maintenance, repair after impeller damage, or when upgrading worn housings and seals to restore reliable raw-water cooling performance.