Water Pump Repair Kit – Fits Mercury/Mariner 2-Stroke 30–70 HP Outboards, Replaces 46-77177A3
Water Pump Repair Kit – Fits Mercury/Mariner 2-Stroke 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 Repair Kit – Fits Mercury/Mariner 2-Stroke 30–70 HP Outb...
Water Pump Repair Kit – Fits Mercury/Mariner 2-Stroke 30–70 HP Outboards, Replaces 46-77177A3 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Pump Repair Kit is designed to service the cooling-system water pump on selected Mercury and Mariner 2-stroke outboards in the 30–70 HP range. It is listed as a replacement for Mercury Marine OEM part number 46-77177A3, also commonly referenced as 77177A3.
The kit is intended to renew the impeller, pump housing and related sealing components so the water pump can maintain proper cooling-water flow. Because Mercury and Mariner applications vary by model, cylinder configuration and serial number, always compare the original pump assembly and verify the complete engine identification before ordering.
- Product type: Water pump repair/service kit
- Engine type: Mercury/Mariner 2-stroke gasoline outboards
- Horsepower range: Selected 30–70 HP applications
- Replacement reference: Mercury Marine 46-77177A3 / 77177A3
- Installation: Direct replacement when the engine and serial-number application match
Part Number Matrix
The following numbers are customer-facing OEM or aftermarket reference numbers associated with this water-pump application. They are provided for cross-reference purposes and do not replace model and serial-number verification.
| Brand | Part Number | Reference |
|---|---|---|
| Mercury Marine | 46-77177A3 | OEM replacement reference |
| Mercury/Mariner | 77177A3 | Alternate OEM-style reference |
| Sierra | 18-3324 | Aftermarket water pump kit cross-reference |
| GLM | 12100 | Aftermarket complete service-kit cross-reference |
| Mallory | 9-48312 | Aftermarket cross-reference |
Engine & Model Compatibility
Fitment depends on the exact model, cylinder configuration and serial-number range. The applications below are documented catalog matches for the 46-77177A3 water pump repair-kit reference. Other 30–70 HP Mercury/Mariner applications may use the same reference, but must be checked against the engine serial number and existing pump components.
| Brand | Model | Rated HP | Stroke | Serial Number | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 30 JET | 30 | Not specified in catalog record | 0C159200–0G589999 | 46-77177A3 | Water pump repair kit listed in gear-housing and jet-components diagrams. |
| Mercury | 30 JET | 30 | Not specified in catalog record | 9570790 and up | 46-77177A3 | Water pump repair kit listed in gear-housing and jet-components diagrams. |
| Mercury | 40, 4-cylinder | 40 | Not specified in catalog record | 0C159200 and up | 46-77177A3 | Verify the pump style and serial number before installation. |
| Mercury | 40, 4-cylinder | 40 | Not specified in catalog record | 9570790 and up | 46-77177A3 | Verify the pump style and serial number before installation. |
Important: The 30–70 HP range is a general cross-reference range, not a confirmation that every engine in that horsepower range uses this kit. Confirm the model designation, cylinder configuration, serial number and original pump layout before purchase.
Technical Specifications
- Product Type
- Aftermarket water pump repair/service kit
- Application
- Selected Mercury and Mariner 2-stroke outboards
- Horsepower Range
- Selected 30–70 HP applications
- Primary OEM Reference
- Mercury Marine 46-77177A3
- Installation
- Direct replacement for a matching water-pump assembly
- Material
- Mixed rubber, elastomer and metal service components
- Warranty
- Refer to the applicable seller warranty and return policy.
What's in the Box
Based on the documented complete water-pump-kit contents associated with this application, the service kit includes the following component types. Individual component appearance may vary by production batch.
- 1 x Water pump impeller
- 1 x Upper pump housing
- 1 x Water pump base
- Water pump and face-plate gaskets
- Drain gasket
- Drain plug
- Metal plate
- O-rings and related sealing rings
Note: A drive key, lower housing, water-tube coupling or other parts shown in some water-pump assemblies are not confirmed as included in this product's documented package contents. Reuse only serviceable original components when the installation instructions require them.
Installation Notes
- Confirm the engine model, cylinder configuration and serial number before beginning work.
- Disconnect the battery and remove the ignition safety lanyard. Follow the outboard manufacturer's service-manual safety procedures.
- Place the engine securely and remove the lower unit according to the service manual.
- Remove the old water-pump housing, impeller, base, plate, gaskets and sealing rings.
- Clean the driveshaft, water-pump cavity and all mating surfaces. Remove old gasket material and inspect for corrosion or scoring.
- Install the replacement gaskets, base, plate, impeller, housing and O-rings in the correct order for the specific engine.
- Apply only the lubricant or sealing compound specified by the service manual. Do not use grease or sealant where it could block a water passage.
- Reinstall the water-pump cover and lower unit, aligning the driveshaft, shift shaft and water tube carefully.
- Tighten fasteners to the manufacturer's specified torque values.
- Run the engine in water or with an appropriate flushing device and confirm a steady cooling-water tell-tale stream before normal operation.
Troubleshooting & FAQ
How do I confirm that this kit fits my engine?
Match the engine brand, model, horsepower, cylinder configuration and serial number with the compatibility information and your manufacturer's parts diagram. The OEM reference alone is not sufficient for engines with multiple pump designs.
What are the signs of a worn water pump?
Common symptoms include a weak or missing tell-tale stream, an overheating warning, rising engine temperature, reduced cooling-water pressure and an impeller with cracked, brittle or missing vanes.
How often should the water pump be serviced?
Inspect and service the impeller according to the engine manufacturer's maintenance schedule. More frequent inspection may be appropriate for engines used in saltwater, sand or silty conditions.
Is this an OEM Mercury part?
No. This is an aftermarket replacement kit intended for engines that use the listed application and OEM reference. Mercury and Mariner are trademarks of their respective owner and are used only to identify compatibility.
Does the kit include every component in the original water-pump assembly?
No. The documented contents cover the repair-kit components listed above. Confirm the package contents and compare them with your engine's diagram before disassembly.
Safety & Important Information
- Verify the engine model, serial number and original pump components before ordering.
- Do not operate an outboard with an uncertain or inadequate cooling-water supply.
- Use the manufacturer's service manual for torque values, assembly order and alignment procedures.
- Professional installation is recommended if you are not experienced with outboard lower-unit or water-pump service.
- This is an aftermarket replacement part and is not manufactured by Mercury Marine or Mariner.
About Sea Sierra
- Marine Replacement Parts — Practical replacement components for routine boat-engine maintenance and repair.
- Application-Focused Listings — Product references and fitment guidance are provided to help you compare the correct part.
- Support for Installation Planning — Always use the engine manufacturer's service information for final fitment and installation details.
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