Water Pump Impeller Repair Kit – Fits Mercury/Mariner 6-9.9 HP Outboards (Replaces 803748Q01, 803750A03, 853792A5)
Water Pump Impeller Repair Kit – Fits Mercury/Mariner 6-9.9 HP Outboards (Replaces 803748Q01, 803750A03, 853792A5) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
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Water Pump Impeller Repair Kit – Fits Mercury/Mariner 6-9.9 HP Outb...
Water Pump Impeller Repair Kit – Fits Mercury/Mariner 6-9.9 HP Outboards (Replaces 803748Q01, 803750A03, 853792A5) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Repair Kit is designed for Mercury and Mariner 8-9.9 HP 4-Stroke (209cc) outboards from 2005 and newer, specifically fitting models with serial number R042475 and up. The kit provides all necessary components for a complete overhaul of the water pump assembly, ensuring proper engine cooling and performance.
It serves as a direct interchange for Mercury part numbers 803748Q01, 803750A03, 853792A5, 47-803748Q01, 47-803750A03, and 803748K01, along with aftermarket references like QuickMarine 803750A03.
- Installation Location: Mounts in the lower unit of the outboard.
- Complete Solution: Includes the impeller, housing, wear plate, gaskets, and cup.
- Durable Materials: Features a neoprene impeller with a hardened nylon hub and a marine-grade nylon housing for longevity.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 803748Q01 |
| Mercury | 803750A03 |
| Mercury | 853792A5 |
| Mercury | 47-803748Q01 |
| Mercury | 47-803750A03 |
| Mercury | 803748K01 |
| QuickMarine | 803750A03 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is verified for specific non-Bigfoot Mercury and Mariner 4-stroke models. Please check your engine's serial number to ensure it is R042475 or higher.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 4-Stroke (209cc) | 8 | 4-Stroke | 2005+ (S/N R042475 & Up) | 803748Q01 | Non-Bigfoot models |
| Mercury | 4-Stroke (209cc) | 9.9 | 4-Stroke | 2005+ (S/N R042475 & Up) | 803748Q01 | Non-Bigfoot models |
| Mariner | 4-Stroke (209cc) | 8 | 4-Stroke | 2005+ (S/N R042475 & Up) | 803748Q01 | International models |
| Mariner | 4-Stroke (209cc) | 9.8 | 4-Stroke | 2005+ (S/N R042475 & Up) | 803748Q01 | International models |
| Mariner | 4-Stroke (209cc) | 9.9 | 4-Stroke | 2005+ (S/N R042475 & Up) | 803748Q01 | International models |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Lower Unit
- Housing Material
- Marine Grade Nylon (Water Pump Housing)
- Housing Color
- Black
- Dimensions
- Impeller Overall Diameter: 1.587 inches (40.3 mm)
Impeller Height: 0.709 inch (18 mm)
Shaft/Hub Size: 0.472 inch (12 mm) - Weight
- 20 g
- Warranty
- 1 Year (for aftermarket versions)
- Other Technical Attributes
- 6-blade impeller design
Neoprene impeller with hardened nylon hub
What’s in the Box
- 1 x Water Pump Impeller (47-8037481)
- 1 x Water Pump Housing (803750A02)
- 1 x Insert Cup (8037511)
- 1 x Wear Plate (8037531)
- 1 x Gasket (161585)
- 1 x Gasket (161586)
- 1 x Gasket (161587)
- 1 x Installation Instructions
Installation Notes
- Disconnect the battery and shift the outboard to the neutral position.
- Drain the gearcase oil from the lower unit.
- Remove the bolts securing the lower unit to the midsection and carefully lower it.
- Unbolt and remove the old water pump housing assembly from the driveshaft.
- Clean the mounting surfaces and inspect the driveshaft for wear or corrosion.
- Install the new wear plate, gaskets, and impeller into the new housing. Ensure the impeller key is correctly seated.
- Slide the new water pump assembly down the driveshaft, aligning the impeller blades correctly with the direction of shaft rotation.
- Secure the new housing with the original bolts, tightening them to the manufacturer's specified torque.
- Reinstall the lower unit, ensuring the water tube and shift shaft are properly aligned.
- Refill the gearcase with fresh oil and test the engine in the water, confirming a steady stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I confirm this kit fits my specific engine?
The most important factor is your engine's serial number. This kit is for Mercury/Mariner 8-9.9 HP 4-stroke (209cc) models from 2005 onwards with a serial number of R042475 and up. Double-check your serial number plate on the transom bracket before ordering.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, and reduced engine performance. A visual inspection may reveal cracked, brittle, or broken impeller blades.
How often should I replace my water pump impeller?
As a preventative maintenance item, it is recommended to replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. Usage in saltwater or sandy/silty conditions may require more frequent replacement.
What is the difference between this full kit and just replacing the impeller?
This is a complete repair kit that includes the housing, wear plate, and gaskets along with the impeller. Over time, the housing and wear plate can warp or score from heat and debris, reducing sealing efficiency. Replacing all components at once ensures a complete and reliable repair, restoring optimal pump performance.
Is this an OEM or aftermarket part?
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.
What are the shipping speed and cost?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free for most regions. Expedited shipping options, if available for your location, will appear at checkout.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal operating conditions. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their original condition. See our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before installation. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement component, not an original equipment manufacturer (OEM) part.
- Professional installation is highly recommended for safety, performance, 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 typical transit times of 5–15 days.
- Manufacturer-Direct Value — Our parts provide fair pricing without ever compromising on materials or quality control.
Payment & Security
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