Water Pump Repair Kit – Fits Mercury & Mariner Outboards 30-70 HP (Replaces 77177A3)
Water Pump Repair Kit – Fits Mercury & Mariner Outboards 30-70 HP (Replaces 77177A3) 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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U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Water Pump Repair Kit – Fits Mercury & Mariner Outboards 30-70 ...
Water Pump Repair Kit – Fits Mercury & Mariner Outboards 30-70 HP (Replaces 77177A3) is backordered and will ship as soon as it is back in stock.
Product Details
This comprehensive Water Pump Repair Kit is designed for Mercury and Mariner 2-cycle outboards from 30 HP through 70 HP (1977–1997). It includes all the essential components for a complete water pump overhaul, ensuring your engine remains properly cooled.
This kit directly replaces Mercury part number 46-77177A3 and is interchangeable with Sierra 18-3324, GLM 12100, and Mallory 9-48312.
- Installation requires removal of the lower unit (gearcase).
- Kit includes a new impeller, housing, face plate, gaskets, and seals.
- Housing components are constructed from durable plastic and metal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 46-77177A3 |
| Sierra | 18-3324 |
| GLM | 12100 |
| Mallory | 9-48312 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury & Mariner models, verify your engine's HP, cylinder count, and serial number range (if provided) to ensure an exact match.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury/Mariner | Jet | 30 | 2-Stroke | 1989–1997 | 77177A3 | 4 cylinders (USA 0C159200-0G589999) |
| Mercury/Mariner | Standard | 35 | 2-Stroke | 1984–1989 | 77177A3 | 2 cylinders |
| Mercury/Mariner | Standard | 40 | 2-Stroke | 1978–1983 | 77177A3 | 2 cylinders (USA 4860103 & below, BEL 9184451 & below) |
| Mercury/Mariner | Standard | 40 | 2-Stroke | 1989–Up | 77177A3 | 4 cylinders |
| Mercury/Mariner | Standard | 45 | 2-Stroke | 1986–Up | 77177A3 | 4 cylinders |
| Mercury/Mariner | Standard | 50 | 2-Stroke | 1978–1985 | 77177A3 | 4 cylinders (USA 5531630 & above) |
| Mercury/Mariner | Standard | 50 | 2-Stroke | 1984–1990 | 77177A3 | 3 cylinders (USA 6428681-0D000749) |
| Mercury/Mariner | Standard | 60 | 2-Stroke | 1984–1990 | 77177A3 | 3 cylinders |
| Mercury/Mariner | Standard | 65 | 2-Stroke | 1976 | 77177A3 | 3 cylinders |
| Mercury/Mariner | Standard | 70 | 2-Stroke | 1977–1983 | 77177A3 | 3 cylinders (USA 4977157-6428680) |
Technical Specs
- Product Type
- Water Pump Repair Kit
- Installation
- Requires lower unit removal
- Housing Material
- Plastic and metal
- Dimensions
- 108mm × 102mm × 95mm (4.25" × 4.00" × 3.75")
- Weight
- 0.34 kg (0.75 lb)
- Warranty
- 1 year (varies by manufacturer)
What’s in the Box
- Water Pump Impeller (89983T)
- Upper Housing
- Lower Housing
- Face Plate
- Face Seal
- Seal Carrier
- Water Tube Coupling
- Drive Key
- Multiple gaskets (quantity varies by manufacturer)
Installation Notes
- Disconnect the battery and shift the outboard into neutral.
- Remove the propeller and drain the gearcase oil.
- Unbolt and carefully lower the gearcase (lower unit) from the driveshaft housing.
- Remove the old water pump housing, impeller, and all associated gaskets and seals.
- Clean all mating surfaces thoroughly, ensuring they are free of old gasket material and corrosion.
- Install the new components in the reverse order of removal, following an OEM service manual for guidance.
- Lightly grease the new impeller and interior of the housing with marine-grade grease before assembly.
- Torque all bolts to the manufacturer's specified values.
- Reinstall the gearcase, refill with fresh gear lube, and reinstall the propeller.
- Reconnect the battery and test the engine in water, confirming a steady stream of water from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my engine?
This kit fits specific Mercury and Mariner 2-stroke outboards from 30–70 HP, manufactured between 1977 and 1997. Always check your engine's model, year, and serial number against our compatibility table. When in doubt, compare the parts in our photos to your old ones.
When should I replace my water pump kit?
For preventative maintenance, we recommend inspecting your impeller annually and replacing the entire water pump kit every 2–3 years or 200–300 hours, whichever comes first. In saltwater or sandy conditions, more frequent replacement is advised.
What are the signs of a failing water pump?
Common symptoms include a weak or intermittent water stream from the "tell-tale" outlet, engine overheating alarms, and in severe cases, steam from the exhaust. A dry-rotted, cracked, or brittle impeller is a clear sign it needs immediate replacement.
Is special knowledge needed to install this kit?
Yes, installation requires removing the lower unit (gearcase), which can be complex. We strongly recommend professional installation unless you are experienced with outboard motor repair and have the appropriate tools and a service manual.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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