Water Pump Impeller Repair Kit for Mercury Marine 30 JET and 35–70 HP 2-Stroke Outboards — Replaces 46-77177A3, 46-77516A3 and 46-73640A2
Water Pump Impeller Repair Kit for Mercury Marine 30 JET and 35–70 HP 2-Stroke Outboards — Replaces 46-77177A3, 46-77516A3 and 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
Orders are typically processed within 1–2 business days.
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Water Pump Impeller Repair Kit for Mercury Marine 30 JET and 35–70 ...
Water Pump Impeller Repair Kit for Mercury Marine 30 JET and 35–70 HP 2-Stroke Outboards — Replaces 46-77177A3, 46-77516A3 and 46-73640A2 is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Repair Kit is intended for selected 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 includes the water-pump components and related gaskets, seals, plates, and hardware shown in the package contents below to help service the engine cooling system.
The kit is listed as a replacement for Mercury part numbers 46-77177A3, 46-77516A3, and 46-73640A2, with additional aftermarket reference numbers from Sierra, GLM, and Mallory. Always confirm the engine model, year, cylinder configuration, and serial-number range before ordering.
- Installs in the lower-unit gearcase water pump.
- Includes a CR-neoprene impeller and seals, nylon pump components, and stainless-steel wear plates.
- Supplies the listed gaskets, O-rings, plates, drain plug, and pump components for the specified applications.
Part Number Matrix
Use these references to compare the listed OEM and aftermarket numbers. They should not be used alone to determine fitment.
| 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 the complete model, cylinder configuration, year, and serial-number range against your engine before purchase.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Serial-Number Conditions |
|---|---|---|---|---|---|---|
| Mercury | JET | 30 | 2-Stroke | 1989–1997 | 46-77177A3 | S/N 0C159200 through 0G589999 |
| Mercury | 2-cylinder | 35 | 2-Stroke | 1984–1989 | 46-77177A3 | S/N 6445653 and up |
| Mercury | 2-cylinder | 40 | 2-Stroke | 1978–1979 | 46-77177A3 | S/N 4860103 through 5556229 |
| Mercury | 2-cylinder | 40 | 2-Stroke | 1980–1983 | 46-77177A3 | S/N 5556230 through 6445653 |
| Mercury | 4-cylinder | 40 | 2-Stroke | 1989 and later | 46-77177A3 | S/N 0C159200 and up |
| Mercury | 4-cylinder | 45 | 2-Stroke | 1986 and later | 46-77177A3 | S/N 5531630 and up |
| Mercury | 4-cylinder | 50 | 2-Stroke | 1978–1985 | 46-77177A3 | S/N 4962056 and up |
| Mercury | 3-cylinder | 50 | 2-Stroke | 1984–1990 | 46-77177A3 | S/N 6428681 through 0D000749 |
| Mercury | 3-cylinder | 60 | 2-Stroke | 1984–1990 | 46-77177A3 | S/N 6428681 through 0D000749 |
| Mercury | 650, 3-cylinder | 65 | 2-Stroke | 1976 | 46-77177A3 | S/N 4382057 through 4571651 |
| Mercury | 3-cylinder | 70 | 2-Stroke | 1979–1983 | 46-77177A3 | S/N 4977157 through 6428680 |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation Location
- Lower-unit gearcase water pump
- Material
- CR-neoprene for the impeller and seals; nylon PA66 for the pump housing and base; stainless steel 316 for the 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)
- Product Status
- Aftermarket replacement kit; not an OEM Mercury part
- Package Configuration
- Includes the impeller, upper pump housing, pump base, plates, gaskets, O-rings, drain plug, and installation instructions listed below
What's in the Box
- 1 × Water Pump Impeller (47-89983 / 18-3007)
- 1 × Upper Pump Housing (46-77822A1 / 18-3118)
- 1 × Water Pump Base (46-77177A1)
- 2 × Plates (27-32770, 27-19551)
- 2 × Drain Gaskets (12-20260, 12-19183)
- 1 × Drain Plug (12-49221)
- 3 × Water Pump Base Gaskets (27-32771, 27-77417, 27-19552)
- 3 × O-Rings (25-26855, 25-45711, 25-26722)
- 1 × Installation Instructions
Installation Notes
- Disconnect the battery and make sure the engine is securely supported before beginning work.
- Shift the outboard into neutral and remove the propeller.
- Unbolt and carefully lower the gearcase from the driveshaft housing. Disconnect the shift shaft if required by the engine design.
- Remove the old water-pump housing, impeller, plates, and related seals, noting the order and orientation of every component.
- Clean all mating surfaces and remove old gasket material, corrosion, and debris.
- Install the supplied components in the correct order. Lightly lubricate the impeller with a suitable water-pump lubricant or clean soapy water as appropriate for the service procedure.
- Reassemble the gearcase and tighten fasteners according to the engine manufacturer's service-manual specifications.
- Refer to the official service manual for detailed procedures, torque values, sealant requirements, and post-installation testing.
Troubleshooting & FAQ
How can I tell if this kit fits my specific motor?
Match the engine's complete model designation, horsepower, cylinder configuration, year, and serial number to the compatibility table. Compare the original pump components and listed part numbers before ordering. If any required detail differs, consult the engine manufacturer's service information or a qualified marine technician.
What are common signs of a failing impeller?
Common symptoms include engine overheating, an overheating alarm or high temperature reading, a weak or intermittent telltale stream, and steam or little water discharge from the cooling-water outlet.
Are there special installation considerations for some Mariner outboards?
Some Japanese-manufactured Mariner applications may require the original housing grommet or seal gasket to be retained if the supplied part does not match the original component. Verify the seal arrangement against the engine service manual before installation.
How often should a water-pump impeller be replaced?
Inspect the impeller as part of regular maintenance. Replacement timing depends on operating hours, storage conditions, saltwater exposure, and sandy or silty water. Follow the engine manufacturer's recommended maintenance interval and replace the impeller sooner if it is damaged, hardened, cracked, or has taken a permanent set.
Is this an OEM or aftermarket part?
This is an aftermarket replacement kit, not an Original Equipment Manufacturer (OEM) Mercury part. Confirm the part numbers and complete fitment conditions before installation.
What are the shipping speed and cost?
Shipping availability, delivery time, and cost depend on the destination and the options shown at checkout.
What is the warranty and return policy?
Return and warranty terms are determined by the retailer and the applicable order policy. Review the policy supplied with your order before installation, and retain the packaging and order information if a return or product-support request is needed.
Safety & Important Information
- Verify the model, year, horsepower, stroke, cylinder configuration, serial-number range, and original part numbers before purchase.
- Do not operate an outboard with inadequate cooling-water flow. Stop the engine immediately if overheating or an abnormal telltale stream occurs.
- This is an aftermarket replacement component, not an OEM part.
- Professional installation is recommended when removing the gearcase or when service-manual procedures and torque specifications are not available.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts designed for demanding freshwater and saltwater service.
- Global Fulfillment — Delivery options and estimated arrival times are displayed according to destination and availability.
- Manufacturer-Direct Value — We work with manufacturing partners to offer practical replacement solutions for marine-maintenance applications.
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