Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4.3L-7.4L V8 (Replaces 47-59362T6, Sierra 18-3087)
Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4.3L-7.4L V8 (Replaces 47-59362T6, Sierra 18-3087) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboa...
Product Details
This Water Pump Impeller Kit – Fits MerCruiser Bravo 1, 2, 3 & Inboard Engines 4.3L-7.4L V8 is designed for MerCruiser Bravo 1, 2, and 3 sterndrives, as well as inboard engines including the 4.3L, 5.0L, 5.7L, and 7.4L V8 models manufactured from 1988 and up (serial number B664190 and later) that use a one-piece pump housing and a serpentine belt.
This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including MerCruiser 47-59362T6, Sierra 18-3087, GLM 12084/89740, and Mallory 9-48316.
- Engine-mounted for one-piece pump housings.
- Designed for raw water and sea water cooling systems.
- Kit includes the neoprene impeller, wear plate, and required O-ring(s) for a complete service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 47-59362T6 |
| MerCruiser | 47-59362 |
| MerCruiser | 47-593621 |
| MerCruiser | 47-59362A1 |
| MerCruiser | 47-59362T1 |
| MerCruiser | 47-59362Q01 |
| Sierra | 18-3087 |
| GLM | 12084 |
| GLM | 89740 |
| Mallory | 9-48316 |
| Mallory | 9-45375-10 |
| Mallory | 9-45375 |
| Jabsco | 17954-0001-P |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser applications, this kit is specifically for models with a one-piece pump housing and serpentine belt, typically from 1988 onwards.
| Model | Engine Size | Drive Type | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Bravo 1, 2, 3 | 4.3L 262 CID V6 | Sterndrive | 1988 and up (Serial# B664190 and up) | 47-59362T6 | For one-piece pump housing |
| Bravo 1, 2, 3 | 5.0L 305 CID V8 | Sterndrive | 1988 and up | 47-59362T6 | For one-piece pump housing |
| Bravo 1, 2, 3 | 5.7L 350 CID V8 | Sterndrive | 1988 and up | 47-59362T6 | For one-piece pump housing |
| Bravo 1, 2, 3 | 7.4L 454 CID V8 | Sterndrive | 1988 and up | 47-59362T6 | For one-piece pump housing |
| 350 MAG/MPI/TBI | 5.7L 350 CID V8 | Inboard | Various | 47-59362T6 | For one-piece pump housing |
| 454 MAG/SKI/TBI | 7.4L 454 CID V8 | Inboard | Various | 47-59362T6 | For one-piece pump housing |
| 260 | V8 | Inboard | 1981–1984 | 47-59362T6 | For one-piece pump housing |
| 340 | V8 | Inboard | 1981–1987 | 47-59362T6 | For one-piece pump housing |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Engine-mounted, one-piece pump housing
- Impeller Material
- Neoprene Rubber
- Impeller Dimensions
- Bore: 0.75 in (19.05 mm), OD: 2.64 in (67.06 mm), Thickness: 2.01 in (51.05 mm)
- Application
- Raw Water/Sea Water Cooling System
- Compatible Drive Types
- Bravo 1, 2, 3 Sterndrives; Inboard Engines
- Compatibility Year Range
- 1988 and up (Serial# B664190 and up)
- Engine Types
- 4.3L, 5.0L, 5.7L, 7.4L V8 with one-piece pump body and serpentine belt
- Housing Type
- For use with one-piece pump housing
What’s in the Box
- 1 x Water Pump Impeller (18-3087)
- 1 x Wear Plate (18-3350)
- 1-2 x O-Ring (18-7163-9)
Installation Notes
- Disconnect the battery and close the seacock/water inlet valve.
- Loosen the serpentine belt and remove it from the water pump pulley.
- Carefully remove the water hoses connected to the pump housing. Have a bucket ready to catch excess water.
- Unbolt and remove the water pump housing from the engine. Note the orientation of the bolts.
- Remove the back cover/wear plate to access the impeller.
- Pry out the old impeller using two flathead screwdrivers or impeller puller tool. Note the rotational direction of the old vanes.
- Clean the inside of the housing and the wear plate surfaces. Replace the wear plate and O-rings with the new ones from the kit.
- Lubricate the new impeller and housing interior with a light coat of grease or soap.
- Install the new impeller, bending the vanes in the correct rotational direction.
- Reinstall the pump housing, hoses, and serpentine belt.
- Open the seacock, reconnect the battery, and start the engine. Check for proper water flow and leaks.
Troubleshooting & FAQ
How do I know if this impeller fits my specific engine?
This kit fits many MerCruiser V6 and V8 engines from 1988+ (Serial# B664190 and up) with a one-piece, engine-mounted raw water pump housing and serpentine belt. Cross-reference your existing impeller or pump part number with those in our Part Number Matrix and check the Engine Compatibility table. Visual comparison is key.
What are the signs of a failing water pump impeller?
Common signs include engine overheating at idle or low speeds, a reduced or no stream of water from the exhaust, and visible cracks or stiffness in the impeller vanes during inspection. Impellers can also degrade and break apart, causing blockages in the cooling system.
How often should I replace my impeller?
As a preventative measure, it is recommended to inspect your impeller annually and replace it every 1-2 years or every 100-200 hours of engine use, depending on operating conditions (especially in sandy or silty water).
Why does the kit sometimes come with one O-ring and sometimes two?
Different batches or aftermarket suppliers may package the kit with either one or two O-rings. Both are intended to provide a complete seal for the compatible pump housings. Use the O-ring that matches the design of your specific pump body.
Is it difficult to install this kit myself?
For individuals with mechanical experience and the right tools, installation is straightforward. However, due to the critical role of the cooling system, professional installation is recommended if you are not completely comfortable with the process.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch inspections for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout where available.
Warranty & returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If any issues arise, 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. Please see our policy page or reach out for instructions.
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.
Payment & Security
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