Water Pump Impeller Repair Kit – Fits MerCruiser Alpha One Gen II & Vazer Drives (Replaces 817275Q05)

Water Pump Impeller Repair Kit – Fits MerCruiser Alpha One Gen II & Vazer Drives

This complete upper water pump service kit is designed for MerCruiser Alpha One Gen II sterndrive units (1991–present) with serial numbers D469859 and above, as well as MerCruiser Vazer drives. It also fits a range of Mercury 2-stroke outboard engines from 225 to 250 HP.

This is a direct aftermarket replacement for Mercury MerCruiser part numbers 817275Q05, 817275A4, 817275A5, 817275K05, 817275Q4, 817275T4, 847275A5, and 817275A1, and can also replace Sierra 18-3147 and GLM 12414.

• Complete Service Kit: Includes all necessary components for a full upper water pump overhaul.
• Durable Construction: Features a robust one-piece stainless steel housing for longevity and corrosion resistance.
• Direct Fit: Engineered to meet OEM specifications for a hassle-free installation.

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 MerCruiser owners, here’s a guide to help you identify your engine’s serial/model: MerCruiser Serial Number Guide. You can also review exploded diagrams to verify part numbers: MerCruiser Parts Diagrams & Catalog.

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.

Technical Specifications

Package Contents

• 1 x Upper Water Pump Housing
• 1 x Impeller (47-43026T-2)
• 1 x Water Guide Fittings
• 1 x Impeller Plate
• 1 x Key
• 1 x Gasket
• 1 x O-Ring
• Additional Gaskets, Seals, and Hardware to make a complete 11-piece kit

Installation Guide

1. Prepare the Drive: Disconnect the battery. Safely secure the vessel and trim the sterndrive to the full up position before removing it from the transom assembly.
2. Access the Pump: Separate the lower unit from the upper unit to expose the water pump assembly.
3. Remove Old Components: Unbolt and remove the existing water pump housing. Carefully pull out the old impeller, wear plate, gaskets, and seals, noting their order and orientation.
4. Clean Surfaces: Thoroughly clean the mounting surfaces, ensuring all old gasket material and sealant are removed.
5. Install New Kit: Assemble the new components in reverse order. Install the new wear plate, gaskets, and key. Apply a light lubricant to the new impeller and inside the new housing.
6. Seat the Impeller: Slide the impeller down the driveshaft, turning the shaft clockwise to seat the vanes correctly within the housing.
7. Reassemble: Install the new housing and tighten the bolts to the manufacturer's specified torque. Reassemble the lower and upper units.
8. Final Check: Reinstall the sterndrive, connect the battery, and test the engine in the water. Ensure a strong, steady stream of water is exiting the tell-tale port.

Troubleshooting & FAQ

How do I confirm this kit fits my MerCruiser Alpha One Gen II drive?
Check your drive's serial number. This kit is specifically for MerCruiser Alpha One Gen II sterndrives with serial numbers D469859 and above (manufactured from 1991 to present) and all MerCruiser Vazer drives.

What are the signs my water pump impeller needs replacement?
Common symptoms include the engine overheating, a weak or inconsistent water stream from the "tell-tale" outlet, or finding brittle, cracked, or missing vanes on your existing impeller during inspection.

How often should I replace the water pump impeller?
As a critical part of preventative maintenance, we recommend replacing the impeller every 1-2 years or every 100-200 hours of use. This interval may be shorter if you operate in saltwater or water with high sediment levels.

Is this a complete kit for the job?
Yes, this is a complete 11-piece kit that contains the upper housing, impeller, wear plate, gaskets, seals, and other hardware required for a full upper water pump service on compatible models.

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.