Water Pump Repair Kit with Housing – Mercury/Mariner/Force 2-Stroke 30–70 HP – Replaces Mercury 46-77177A3 and Sierra 18-3324
Water Pump Repair Kit with Housing – Mercury/Mariner/Force 2-Stroke 30–70 HP – Replaces Mercury 46-77177A3 and Sierra 18-3324 is backordered and will ship as soon as it is back in stock.
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Water Pump Repair Kit with Housing – Mercury/Mariner/Force 2-Stroke...
Water Pump Repair Kit with Housing – Mercury/Mariner/Force 2-Stroke 30–70 HP – Replaces Mercury 46-77177A3 and Sierra 18-3324 is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit with Housing is an aftermarket replacement kit for selected Mercury, Mariner, and Force 2-stroke outboards in the 30–70 HP range. Catalog references identify this application for 30 Jet, 35, 40, 45, 50, 60, and 70 HP engines, generally covering 1970–1986 applications. The kit is intended to restore water-pump components that are worn, damaged, or no longer sealing correctly.
The kit replaces Mercury Marine 46-77177A3 and is listed as Sierra 18-3324. These are manufacturer or aftermarket reference numbers, not the seller's internal product identifier.
- Complete water-pump repair kit with impeller, pump housing, water-pump base, plate, gaskets, and O-rings.
- Designed for selected Mercury/Mariner/Force 2-stroke cooling-system applications.
- Confirm the engine model, horsepower, year, serial number, pump-base style, and original component dimensions before ordering.
Part Number Matrix
Use the following references to compare the kit with your existing water-pump components and catalog information.
| Brand or source | Reference number | Reference type |
|---|---|---|
| Mercury Marine | 46-77177A3 | OEM reference replaced by this kit |
| Sierra | 18-3324 | Aftermarket water pump kit reference |
| GLM | 12100 | Catalog cross-reference for the 46-77177A3 application |
Engine & Model Compatibility
Compatibility depends on the complete model and serial-number condition, not horsepower alone. The application information below is a consolidated guide; verify the exact engine catalog and compare the existing pump base and housing before installation.
| Brand | Model or application | Rated HP | Stroke | Application years | Fitment notes |
|---|---|---|---|---|---|
| Mercury / Mariner | 30 Jet | 30 | 2-Stroke | Catalog application varies by serial range | Catalog occurrences include serial range 0C159200 through 0G589999 and a separate 9570790-and-up application. Confirm the serial number. |
| Mercury / Mariner / Force | Selected 35, 40, 45, 50, 60, and 70 HP models | 35–70 | 2-Stroke | Generally 1970–1986 | Application depends on the pump-base and housing configuration. Do not use horsepower alone to confirm fit. |
| Mercury | 40, 4-cylinder application | 40 | 2-Stroke | Serial-dependent | Catalog occurrences include serial ranges beginning at 0C159200 and 9570790. Verify the full serial range and component configuration. |
Important: The available catalog evidence does not establish every individual model, year, cylinder configuration, or serial range within the 30–70 HP range. If your engine falls outside the listed application conditions, compare the original part numbers and pump-base style with a current parts diagram before purchase.
Technical Specifications
- Product type
- Water pump repair kit with upper housing and water-pump base
- Application
- Selected Mercury, Mariner, and Force 2-stroke outboards, primarily 30–70 HP applications
- Replacement reference
- Mercury Marine 46-77177A3; Sierra 18-3324
- Installation
- Replacement water-pump assembly; installation requires removal of the lower unit and access to the driveshaft and water-pump components
- Included component types
- Impeller, upper pump housing, water-pump base, plate, gaskets, drain plug, and O-rings
- Material and color
- Not specified in the verified catalog records
- Weight
- Not specified in the verified catalog records
What's in the Box
The Sierra catalog description for the corresponding water pump kit identifies the following components and quantities:
- 1 x Impeller
- 1 x Upper pump housing
- 1 x Water-pump base
- 2 x Drain gasket
- 1 x Lower water-pump-base-to-face-plate gasket
- 1 x Upper face-plate-to-body gasket
- 1 x Water-pump-base gasket
- 1 x Additional water-pump-base gasket
- 1 x Drain plug
- 1 x Plate
- 1 x O-ring
- 1 x O-ring
- 1 x O-ring
Component appearance and exact printed markings may vary by production batch. Compare the supplied parts with the removed components before assembly.
Installation Notes
- Refer to the engine manufacturer's service manual for safety procedures, torque specifications, serial-number limits, and lower-unit removal instructions.
- Disconnect the battery where applicable and secure the engine before working on the lower unit.
- Remove the lower unit and note the positions of the driveshaft, water tube, shift shaft, and existing pump components.
- Remove the old housing, impeller, plate, gaskets, O-rings, and water-pump base as required by the engine design.
- Clean all mating surfaces and inspect the driveshaft, keyway, water tube, water passages, and pump cavity for wear or blockage.
- Install the new gaskets, plate, impeller, housing, base, drain plug, and O-rings in the order specified by the service manual.
- Position the impeller vanes in the correct direction for the driveshaft rotation and use an approved lubricant where specified.
- Reinstall the lower unit, align the driveshaft, water tube, and shift shaft, and tighten fasteners to the manufacturer's specifications.
- Test the engine with an appropriate water supply and confirm a strong cooling-water telltale stream before normal operation.
Troubleshooting & FAQ
How do I confirm that this kit fits my engine?
Check the complete engine brand, model, horsepower, stroke, year, and serial number. Then compare the original pump-base and housing configuration and the reference number 46-77177A3 or 18-3324. Horsepower alone is not sufficient for confirmation.
What are common signs of a worn water-pump impeller?
Common symptoms include overheating, a weak or missing telltale stream, reduced cooling-water flow, damaged or stiff impeller vanes, or visible cracking and deformation during inspection.
Does this kit include a housing and water-pump base?
Yes. The catalog description identifies an upper pump housing and a water-pump base in addition to the impeller, plate, gaskets, drain plug, and O-rings.
Does this kit include every part listed in the original engine diagram?
No. This kit contains the components listed in the package section above. Other lower-unit or cooling-system parts may be separate items for a particular engine.
Why might the new water pump still have weak flow?
Possible causes include an incorrectly installed impeller, blocked water passages, a damaged water tube or seal, incorrect gasket placement, a worn pump cavity, or a thermostat or cooling-system fault. Follow the engine service manual for diagnosis.
Is this an OEM part?
No. This is an aftermarket replacement kit that references Mercury Marine 46-77177A3 and Sierra 18-3324 for identification and application comparison.
What warranty, shipping, and return terms apply?
Warranty, shipping, and return terms depend on the seller's current policies and order destination. Review the applicable policy information at checkout or contact customer support before ordering.
Safety & Important Information
- Confirm the exact model, year, stroke, serial range, and pump-base configuration before purchase.
- Do not operate an outboard without an adequate cooling-water supply.
- Use the manufacturer's service manual for disassembly, torque values, sealants, and final testing.
- Professional installation is recommended if you are unfamiliar with lower-unit or water-pump service.
- This is an aftermarket replacement, not an OEM Mercury Marine component.
About Sea Sierra
- Marine Replacement Parts — Practical aftermarket components for maintenance and repair applications.
- Fitment-Focused Information — Use manufacturer references, engine specifications, and serial-number conditions to select the correct part.
- Support for Installation Planning — Compare the original assembly and service-manual requirements before beginning work.
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