Water Pump Impeller Kit – Fits Mercury/Mariner 30-70 HP (Replaces 46-77177A3, 77177A3)
Water Pump Impeller Kit – Fits Mercury/Mariner 30-70 HP (Replaces 46-77177A3, 77177A3) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Water Pump Impeller Kit – Fits Mercury/Mariner 30-70 HP (Replaces 4...
Water Pump Impeller Kit – Fits Mercury/Mariner 30-70 HP (Replaces 46-77177A3, 77177A3) is backordered and will ship as soon as it is back in stock.
Product Details
This complete Water Pump Impeller Kit – Fits Mercury/Mariner 2-Cycle 30-70 HP (Replaces 46-77177A3, 77177A3) provides everything needed to restore your engine's cooling system. It is designed for Mercury/Mariner 2-Stroke outboards from 30 HP to 70 HP, covering models from 1976–1997, including 30 JET, 35, 40, 45, 50, 60, 65, and 70 HP variants.
This kit serves as a direct interchange for several part numbers, including Mercury 46-77177A3, Sierra 18-3324, GLM 12100, Mallory 9-48312, and Quicksilver 77177A3.
- Engineered for direct OEM replacement installation.
- The housing combines durable PA66 Nylon plastic for the upper section with a stainless steel cup and plate for corrosion resistance.
- Includes a high-quality neoprene rubber impeller, gaskets, plates, and all necessary hardware for a full service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 46-77177A3 / 77177A3 |
| Quicksilver | 77177A3 |
| Sierra | 18-3324 |
| SeaSierra | 183324 |
| GLM | 12100 |
| Mallory | 9-48312 |
| NorthBoat | 77177A3 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is designed for a range of Mercury and Mariner 2-stroke outboard engines from 30 to 70 HP. Please check your serial number to ensure correct fitment, as specified in the notes.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury/Mariner | Outboard | 30 JET | 2-Stroke | 1989–1997 | 46-77177A3 | Serial #9570790 & Up |
| Mercury/Mariner | Outboard | 35 | 2-Stroke | 1984–1989 | 46-77177A3 | 2 Cylinder (S/N 6445653 & Up) |
| Mercury/Mariner | Outboard | 40 | 2-Stroke | 1978–1979 | 46-77177A3 | 2 Cylinder (S/N 4860103-5556229) |
| Mercury/Mariner | Outboard | 40 | 2-Stroke | 1980–1983 | 46-77177A3 | 2 Cylinder (S/N 5556230-6445653) |
| Mercury/Mariner | Outboard | 40 | 2-Stroke | 1989-Up | 46-77177A3 | 4 Cylinder (S/N 0C159200 & Up) |
| Mercury/Mariner | Outboard | 45 | 2-Stroke | 1986-Up | 46-77177A3 | 4 Cylinder (S/N 5531630 & Up) |
| Mercury/Mariner | Outboard | 50 | 2-Stroke | 1978–1985 | 46-77177A3 | 4 Cylinder (S/N 4962056 & Up) |
| Mercury/Mariner | Outboard | 50 | 2-Stroke | 1984–1990 | 46-77177A3 | 3 Cylinder (S/N 6428681-0D000749) |
| Mercury/Mariner | Outboard | 60 | 2-Stroke | 1984–1990 | 46-77177A3 | 3 Cylinder (S/N 6428681-0D000749) |
| Mercury/Mariner | Outboard | 65 | 2-Stroke | 1976 | 46-77177A3 | 3 Cylinder (S/N 4382057-4571651) |
| Mercury/Mariner | Outboard | 70 | 2-Stroke | 1977–1983 | 46-77177A3 | 3 Cylinder (S/N 4977157-6428680) |
Technical Specs
- Product Type
- Water Pump Impeller Kit with Housing
- Installation
- Direct OEM replacement
- Housing Material
- PA66 Nylon Plastic (Upper Housing), Stainless Steel (Cup and Plate)
- Impeller Material
- Neoprene Rubber
- Housing Color
- Black
- Weight
- 294 g (0.65 lb)
- Warranty
- Varies by manufacturer (lifetime warranty from some aftermarket suppliers)
- Other Technical Attributes
- Complete kit including impeller, housing, base, plates, gaskets, and necessary hardware
What’s in the Box
- 1 x Impeller (47-20268)
- 1 x Impeller Plate (32768)
- 1 x Impeller Key
- 1 x Water Pump Housing (46-48746A1)
- 1 x Water Pump Base (46-77177A1)
- 1 x Water Pump Base Gasket (27-32771)
- 1 x Water Pump Base Gasket (27-77417)
- 1 x Lower Water Pump Gasket (27-32769)
- 1 x Upper Water Pump Gasket (27-19551)
- 2 x Drain Screw Gasket (12-19183)
- 1 x Rubber Washer (12-49221)
- 3 x O-Ring
- 1 x Exhaust Leg Rubber Seal (37721) (Note: included in some kits)
Installation Notes
- Disconnect the battery and shift the outboard into neutral.
- Remove the lower unit (gearcase) by unbolting it from the engine's midsection. Be prepared for it to be heavy.
- Locate the water pump housing, typically on top of the lower unit, and remove the bolts securing it.
- Slide the old housing and impeller off the driveshaft. Note the orientation of the impeller vanes.
- Clean the mounting surfaces and inspect the driveshaft for wear.
- Install the new gaskets, wear plate, and impeller key. Slide the new impeller onto the shaft, rotating it in the direction of engine rotation to bend the vanes correctly.
- Apply a light coat of marine grease to the inside of the new housing and install it over the impeller.
- Secure the new housing with bolts, tightening them to the manufacturer's specified torque.
- Reinstall the lower unit, ensuring the driveshaft and water tube align correctly.
- Reconnect the battery and test the engine using a water supply (flushing muffs) to confirm a strong water stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my exact engine?
The best way to ensure fitment is to match your engine's model, horsepower, year, and serial number to the information in the Engine & Model Compatibility table. Serial number ranges are critical for many models.
What are the signs of a failing water pump impeller?
Common signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet, and a dry, cracked, or deformed appearance of the old impeller upon inspection.
How often should I replace my water pump impeller?
For preventative maintenance, it's recommended to replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. Consult your engine's service manual for specific intervals.
Is there anything special about installing the new impeller?
Yes, ensure the impeller vanes are bent in the correct direction during installation. Lubricating the inside of the pump housing with marine grease helps the impeller seat correctly and prevents damage during the first startup.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). 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.
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