Water Pump Impeller Kit Without Housing – Fits Mercury/Mariner 30–70 HP Outboards, Replaces 46-77177A3
Water Pump Impeller Kit Without Housing – Fits Mercury/Mariner 30–70 HP Outboards, Replaces 46-77177A3 is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Kit Without Housing – Fits Mercury/Mariner 30–7...
Water Pump Impeller Kit Without Housing – Fits Mercury/Mariner 30–70 HP Outboards, Replaces 46-77177A3 is backordered and will ship as soon as it is back in stock.
Product Details
This water pump impeller kit without housing is intended to service the water pump assembly on compatible Mercury and Mariner outboard engines in the 30–70 HP range. It helps restore water circulation and cooling performance when the existing pump housing remains serviceable.
The kit is listed as a replacement for Mercury Marine part number 46-77177A3. The pump housing is not included.
- Aftermarket replacement water pump impeller service kit.
- Designed for use with the existing water pump housing and related reusable hardware.
- Includes the service components listed below; quantities should be checked against the parts received before installation.
- Water pump housing is not included.
Part Number References
Use the following reference to compare your original part before ordering. Part-number references do not replace verification of the complete engine model, serial number, and pump configuration.
| Brand or Reference | Part Number | Description |
|---|---|---|
| Mercury Marine | 46-77177A3 | Water pump repair-kit reference; housing not included with this listing |
| Alternate format | 77177A3 | Reference associated with the same base part number |
Engine Compatibility
Catalog data associates part number 46-77177A3 with selected Mercury 30 HP and 40 HP applications, including model and serial-number conditions. Additional aftermarket references list the part across a broader 30–70 HP range. Because water-pump fitment can change by model, gearcase, serial number, and configuration, verify your exact engine application before installation.
| Brand | Rated HP Range | Stroke | Model / Serial Requirement | Fitment Note |
|---|---|---|---|---|
| Mercury / Mariner | 30–70 HP | Not specified | Verify exact model and serial number | Use the original part number and pump configuration for final confirmation |
| Mercury | 30 HP | Not specified | Catalog examples include 30 JET with serial ranges 0C159200–0G589999 and 9570790 and up | These are catalog examples, not a complete application list |
| Mercury | 40 HP | Not specified | Catalog examples include 40 (4 CYL.) with serial ranges 0C159200 and up and 9570790 and up | Confirm the exact serial range before ordering |
Technical Specifications
- Product Type
- Water pump impeller service kit
- Housing
- Not included
- Installation
- Replacement service part; installation requires removal and reassembly of the applicable water pump components
- Primary Reference
- Mercury Marine 46-77177A3
- Brand Status
- Aftermarket replacement, not an OEM-branded component
What's in the Box
- 1 x Water pump impeller
- Gaskets and seals for the water pump service
- 1 x Drive key
- 1 x Face plate
- 1 x Face seal
- 1 x Seal carrier
- 1 x Water tube coupling
- Not included: water pump housing
Component appearance and exact quantity may vary by production batch. Compare the supplied components with the original pump assembly and service-manual parts diagram before installation.
Installation Notes
- Disconnect the battery and follow the engine manufacturer's safety procedures.
- Place a drain pan under the lower unit. If required by the service procedure, drain the gearcase lubricant.
- Remove the gearcase according to the service-manual procedure, taking care to support the unit and protect the shift shaft, driveshaft, and water tube.
- Remove the water pump cover or housing and inspect the existing housing, wear surfaces, plate, and base for scoring, cracks, distortion, or heat damage.
- Remove the old impeller and drive key. Note the original vane direction before removal.
- Clean the mating surfaces and install the replacement gaskets, seals, plate, key, and impeller supplied with the kit.
- Install the impeller with the vanes oriented in the direction of engine rotation. Use an appropriate lubricant compatible with the impeller material.
- Reinstall the existing pump housing only if it is in serviceable condition. Do not use a damaged or severely scored housing.
- Reinstall the gearcase, aligning the driveshaft, shift shaft, and water tube. Tighten fasteners to the manufacturer's specifications.
- Refill the gearcase if it was drained, reconnect the battery, and test the engine with an appropriate water supply.
- Confirm a steady tell-tale stream and monitor for overheating or abnormal water-pressure indications.
Troubleshooting & FAQ
Does this kit include the water pump housing?
No. This listing is for an impeller service kit without the water pump housing. Reuse your existing housing only after confirming that it is not cracked, warped, melted, or excessively scored.
How do I confirm compatibility?
Compare the original part number, engine brand, horsepower, model, serial number, gearcase configuration, and water-pump diagram. The 30–70 HP range is a general application guide and is not a substitute for exact model and serial-number verification.
What are common signs of a failing impeller?
Common signs include a weak or missing tell-tale stream, overheating warnings, reduced water pressure, or visible impeller damage. A blocked cooling passage, failed thermostat, worn plate, or damaged housing can cause similar symptoms.
How often should the impeller be inspected or replaced?
Impeller service intervals depend on the engine manufacturer's schedule and operating conditions. Inspect it regularly and replace it sooner when the engine is used in sandy, silty, salty, or debris-filled water.
Will replacing the impeller correct an overheating engine?
A worn or damaged impeller can cause overheating, but it is not the only possible cause. If overheating continues after installation, inspect the housing, wear plate, thermostat, cooling passages, water tube, and water-pressure system.
Is this an OEM part?
No. This is an aftermarket replacement kit intended to replace the referenced water-pump service part. It is not manufactured or branded by Mercury Marine.
Safety & Important Information
- Verify the complete engine model and serial number before ordering.
- Do not rely on horsepower alone to determine fitment.
- Inspect the existing housing and wear surfaces before installing a new impeller.
- Follow the engine service manual for disassembly, torque values, lubrication, and testing.
- Professional installation is recommended when the lower unit or cooling system cannot be safely serviced by the owner.
About Sea Sierra
- Marine Replacement Parts — Practical aftermarket components for routine maintenance and repair.
- Application-Focused Support — Confirm the engine model, serial number, and original part before ordering.
- Service-Ready Selection — Parts are selected for common marine maintenance and replacement applications.
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