Water Pump Impeller Kit – Fits Mercury/MerCruiser Alpha One Gen 2 & Outboard 40-250 HP (Replaces 8M0100526, 47-43026Q06)
Water Pump Impeller Kit – Fits Mercury/MerCruiser Alpha One Gen 2 & Outboard 40-250 HP (Replaces 8M0100526, 47-43026Q06) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Impeller Kit – Fits Mercury/MerCruiser Alpha One Gen 2 &...
Product Details
This Water Pump Impeller Kit is an essential service part for maintaining the cooling system on a wide range of Mercury engines. It is designed to fit MerCruiser Alpha One Gen 2 sterndrives (1998 and newer, serial #0D469859 and up) as well as numerous Mercury and Mariner outboard models from 40 HP to 250 HP, covering 2-stroke, 4-stroke, BigFoot, Command Thrust, OptiMax, and Verado series engines.
The kit serves as a direct aftermarket replacement for multiple OEM and Quicksilver part numbers, including 8M0100526, 47-8M0100526, 47-43026Q06, and Sierra 18-3265, ensuring broad compatibility.
- Engineered for durability with a neoprene rubber impeller that improves flexibility across a wide range of temperatures for reliable performance.
- Designed for direct replacement of the original, allowing for straightforward installation with basic tools.
- The comprehensive package includes the impeller, wear plate, gaskets, seals, and O-rings needed for a complete water pump service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/Quicksilver | 8M0100526 |
| Mercury/Quicksilver | 47-8M0100526 |
| Mercury/Quicksilver | 47-43026Q06 |
| Mercury/Quicksilver | 43026T11 |
| Mercury/Quicksilver | 43026T10 |
| Mercury/Quicksilver | 43026T8 |
| Mercury/Quicksilver | 43026T7 |
| Mercury/Quicksilver | 43026T6 |
| Mercury/Quicksilver | 43026Q5 |
| Sierra | 18-3265 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser applications, this kit is compatible with Alpha One Gen 2 sterndrives manufactured from 1998 onwards (serial #0D469859 and above).
For Mercury outboards, verify compatibility using your engine model, horsepower, and serial number as specified in the chart.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | Alpha One Gen 2 | N/A | N/A | 1998 and up | 47-8M0100526 | Serial #0D469859 and above |
| MerCruiser | QS Alpha One | N/A | N/A | N/A | 47-8M0100526 | Serial #2A629407 and above |
| Mercury | 40/50/60 BigFoot/Command Thrust | 40-60 | 4-Stroke | N/A | 47-8M0100526 | EFI models |
| Mercury | BigFoot | 60 | 2-Stroke | N/A | 47-8M0100526 | Serial #0D000750 and above |
| Mercury | 75/90/115 | 75-115 | 4-Stroke | N/A | 47-8M0100526 | All models |
| Mercury | 150 | 150 | 4-Stroke | N/A | 47-8M0100526 | EFI models |
| Mercury | 70/75/80/90 | 70-90 | 2-Stroke | N/A | 47-8M0100526 | Serial #0A996142 and above |
| Mercury | 100/115/125 (4 cyl) | 100-125 | 2-Stroke | N/A | 47-8M0100526 | Models having pump cover screws without insulators |
| Mercury | V-200/225/250 (3.0L) | 200-250 | 2-Stroke | N/A | 47-8M0100526 | OptiMax models |
| Mercury | Verado L4 & L6 | 135-275 | 4-Stroke | N/A | 47-8M0100526 | With 4.80" & 5.44" diameter gearcases |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Direct replacement, requires basic tools
- Impeller Material
- Neoprene rubber
- Weight
- 0.24 kg (8.4 oz)
- Warranty
- 1 year factory warranty against defects and workmanship
- Technical Note
- Impeller elastomers provide improved flexibility across broad temperature ranges for enhanced durability and flow rates.
What’s in the Box
- 1 x Water Pump Impeller (8M0025709, 47-43026Q02)
- 1 x Impeller Drive Key (8M0032833, 28-43037)
- 1 x Water Pump Faceplate (8172761)
- 1 x Faceplate Gasket (8M0050720, 27-43033-1)
- 1 x Water Pump Gasket (8172771, 27-8172771)
- 1 x Quad Ring/Seal Ring (455771, 26-45577)
- 1 x Face Seal (8M2014338, 26-816575A2)
- 1 x Face Seal Setting Tool (818769)
- 2 x O-ring (0.796 in. x 0.139 in.) (21836, 25-21836)
- 1 x O-ring (0.921 in. x 0.139 in.) (90196, 25-90196, 18-7178)
- 2 x Drain Plug Seal (830749, 26-830749)
- 1 x Water Tube (32-860220) - Note: included in some kits but not all.
Installation Notes
- Disconnect the battery and remove the engine kill switch safety lanyard.
- Place the outboard or sterndrive in forward gear to simplify driveshaft alignment during reassembly.
- Position a drain pan under the lower unit and remove the gearcase oil drain/fill screws to drain the lubricant.
- Unbolt and carefully separate the lower unit (gearcase) from the upper housing. You may need to disconnect the speedometer tube if equipped.
- Remove the bolts securing the water pump housing to the gearcase.
- Slide the old water pump assembly up and off the driveshaft. Note the orientation of all parts.
- Remove the old impeller, key, gaskets, and wear plate, and clean all mounting surfaces thoroughly.
- Install the new gaskets, wear plate, impeller, and key from the kit. Ensure the impeller vanes are oriented correctly (typically by turning the driveshaft clockwise while pushing the housing down).
- Install the new housing and seals. Torque bolts to manufacturer specifications.
- Re-install the lower unit, ensuring the driveshaft, shift shaft, and water tube align correctly.
- Refill the gearcase with fresh marine gear lubricant from the bottom fill hole until it seeps from the top vent hole.
- Start the engine in water and confirm a steady stream of water is exiting the cooling system tell-tale outlet. Check for leaks.
Troubleshooting & FAQ
How do I know if this kit fits my engine?
The most reliable method is to match your engine's serial number against the ranges listed in the compatibility table. This kit fits MerCruiser Alpha One Gen 2 drives with serial #0D469859 and up, and various Mercury outboards where the model and serial number ranges align with the chart.
What are signs of a failing impeller?
Common symptoms of a worn or damaged impeller include the engine running hotter than normal, an alarm sounding, a weak or non-existent stream of water from the "telltale" outlet, and visible cracks or brittleness on the old impeller vanes upon inspection.
How often should I replace my water pump impeller?
As a crucial part of preventative maintenance, it is best practice to replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. This helps prevent sudden failure and catastrophic engine damage from overheating.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. All parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free to most locations; expedited options will appear at checkout if available for your region.
Warranty & returns
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears on a compatible list—do not install the part.
- This is an aftermarket replacement component, not an Original Equipment Manufacturer (OEM) part. Part numbers are for reference only.
- Professional installation is highly recommended for safety, proper function, and to prevent damage to your engine.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions with a typical transit time of 5–15 days.
- Manufacturer-Direct Value — Our parts deliver fair pricing without compromising on high-quality materials or quality control.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
