Water Pump Impeller Repair Kit – Fits Mercury Marine 30 JET, 35-70 HP Outboards (Replaces 46-77177A3, 46-77516A3, 46-73640A2)
Water Pump Impeller Repair Kit – Fits Mercury Marine 30 JET, 35-70 HP Outboards (Replaces 46-77177A3, 46-77516A3, 46-73640A2) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Water Pump Impeller Repair Kit – Fits Mercury Marine 30 JET, 35-70 ...
Water Pump Impeller Repair Kit – Fits Mercury Marine 30 JET, 35-70 HP Outboards (Replaces 46-77177A3, 46-77516A3, 46-73640A2) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Repair Kit is designed for a range of 2-stroke Mercury Marine and Mariner outboard motors, including 30 JET, 35 HP, 40 HP, 45 HP, 50 HP, 60 HP, 65 HP, and 70 HP models manufactured between 1976 and 1997. It contains all necessary components to restore the engine’s cooling system, preventing overheating and ensuring reliable operation.
It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 46-77177A3, 46-77516A3, and 46-73640A2, as well as equivalents from Sierra, GLM, and Mallory.
- Installs in the lower unit gearcase.
- Constructed from marine-grade neoprene, nylon, and stainless steel for durability.
- Includes a complete set of gaskets, seals, and housings for a full rebuild.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 46-77177A3 |
| Mercury | 46-77516A3 |
| Mercury | 46-73640A2 |
| Sierra | 18-3322 |
| Sierra | 18-3323 |
| Sierra | 18-3324 |
| GLM | 12170 |
| GLM | 12180 |
| GLM | 12100 |
| Mallory | 9-48303 |
| Mallory | 9-48302 |
| Mallory | 9-48312 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | JET | 30 | 2-Stroke | 1989–1997 | 46-77177A3 | S/N 0C159200 through 0G589999 |
| Mercury | (2 CYL.) | 35 | 2-Stroke | 1984–1989 | 46-77177A3 | S/N 6445653 & Up |
| Mercury | (2 CYL.) | 40 | 2-Stroke | 1978–1979 | 46-77177A3 | S/N 4860103 through 5556229 |
| Mercury | (2 CYL.) | 40 | 2-Stroke | 1980–1983 | 46-77177A3 | S/N 5556230 through 6445653 |
| Mercury | (4 CYL.) | 40 | 2-Stroke | 1989–Up | 46-77177A3 | S/N 0C159200 & Up |
| Mercury | (4 CYL.) | 45 | 2-Stroke | 1986–Up | 46-77177A3 | S/N 5531630 & Up |
| Mercury | (4 CYL.) | 50 | 2-Stroke | 1978–1985 | 46-77177A3 | S/N 4962056 & Up |
| Mercury | (3 CYL.) | 50 | 2-Stroke | 1984–1990 | 46-77177A3 | S/N 6428681 through 0D000749 |
| Mercury | (3 CYL.) | 60 | 2-Stroke | 1984–1990 | 46-77177A3 | S/N 6428681 through 0D000749 |
| Mercury | 650 (3 CYL.) | 65 | 2-Stroke | 1976 | 46-77177A3 | S/N 4382057 through 4571651 |
| Mercury | (3 CYL.) | 70 | 2-Stroke | 1979–1983 | 46-77177A3 | S/N 4977157 through 6428680 |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Lower Unit Gearcase
- Material
- Marine Grade CR-Neoprene (Impeller and Seals), Nylon PA66 (Housing and Base), Stainless Steel 316 (Wear Plate)
- Package Dimensions
- 15.7 × 10.3 × 8.2 cm (6.14 × 4.06 × 3.23 in)
- Weight
- 0.35 kg (12.3 oz)
- Warranty
- Standard 30-day return through retailers
- Other Attributes
- Complete kit including upper and lower housings
What’s in the Box
- 1 x Water Pump Impeller (47-89983/18-3007)
- 1 x Upper Pump Housing (46-77822A1/18-3118)
- 1 x Water Pump Base (46-77177A1)
- 2 x Plates (27-32770, 27-19551)
- 2 x Drain Gaskets (12-20260, 12-19183)
- 1 x Drain Plug (12-49221)
- 3 x Water Pump Base Gaskets (27-32771, 27-77417, 27-19552)
- 3 x O-Rings (25-26855, 25-45711, 25-26722)
- 1 x Installation Instructions
Installation Notes
- Before starting, disconnect the battery and ensure the engine is securely mounted.
- Shift the outboard into neutral and remove the propeller.
- Unbolt and carefully lower the gearcase from the driveshaft housing. Disconnect the shift shaft if necessary.
- Remove the old water pump housing, impeller, and wear plate, noting the order of all parts.
- Clean all mating surfaces thoroughly, removing any old gasket material or debris.
- Install the new components from the kit in the reverse order of removal. Lightly grease the new impeller to ease installation.
- Reassemble the gearcase, ensuring all bolts are torqued to the manufacturer’s specifications.
- Refer to your outboard's official service manual for detailed procedures and torque values.
Troubleshooting & FAQ
How can I tell if this kit fits my specific motor?
The most reliable method is to match your engine's serial number (S/N) to the ranges listed in the compatibility table. Also verify the model, horsepower, and year range. If in doubt, compare images to your existing parts before ordering.
What are common signs of a failing impeller?
The primary symptom is engine overheating, often indicated by an alarm or temperature gauge. Other signs include a weak or inconsistent stream of water from the "telltale" outlet and, in severe cases, steam instead of water.
My outboard is Japanese-made. Are there special installation notes?
Yes. For some Japanese-manufactured Mariner outboards, you may need to retain and reuse the original housing grommet seal gasket, as the one supplied in the kit may not fit. For non-Japanese models, a separate grommet kit (part no. 26-38452/26-38453) is recommended.
How often should a water pump impeller be replaced?
As a general maintenance guideline, inspect the impeller annually and plan for replacement every 1-2 years or every 100-200 hours of operation, whichever comes first. This interval can vary based on usage conditions (e.g., saltwater vs. freshwater, sandy/silty water).
Is this an OEM or aftermarket part?
This listing is an aftermarket replacement (not OEM). It has been built to meet or exceed OEM-level specifications with comparable high-quality materials. We ensure our parts are manufactured in an ISO 9002 certified 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 orders, with expedited options available at checkout where applicable.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use. Should an issue arise, please contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original packaging. See our policy page or reach out for detailed instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. 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, proper function, and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world saltwater and freshwater conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with typical arrival in 5–15 days.
- Manufacturer-Direct Value — By working directly with our manufacturing partners, we provide fair pricing without compromising on materials or quality control.
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