Water Pump Impeller Gasket – Fits Yamaha & Mariner 20–30 HP Outboards
This water pump impeller gasket is engineered for Yamaha and Mariner 2-stroke outboard engines rated 20–30 HP. It ensures a reliable seal between impeller housing components, preventing water leaks and maintaining optimal cooling system performance across a range of models from the mid-1980s.
Direct Replacement for: Yamaha 689-44316-A0
- Compatible with Yamaha 2-stroke 25–30 HP (1984–1985) and Mariner 20–30 HP (various series)
- Precise OEM-specification fitment for impeller housing assembly
- Essential component for water pump maintenance and rebuild
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Yamaha |
689-44316-A0 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.
| Brand |
Model |
Rated HP |
Stroke |
Years |
Notes |
| Yamaha |
Outboard |
25 HP |
2-Stroke |
1984–1985 |
|
| Yamaha |
Outboard |
30 HP |
2-Stroke |
1984–1985 |
|
| Mariner |
20C |
20 HP |
|
All Years |
S/N prefix 6A9 |
| Mariner |
25C |
25 HP |
|
All Years |
S/N prefix 6A9 |
| Mariner |
30A |
30 HP |
|
All Years |
S/N prefix 684 |
Technical Specifications
| Specification |
Value |
| OEM Part Number |
689-44316-A0 |
| Application |
Water Pump Impeller Housing Gasket |
| Fitment |
Yamaha 20–30 HP, Mariner 20–30 HP |
Package Contents
- 1 × Impeller Gasket (Yamaha 689-44316-A0-00)
Installation Guide
- Disconnect the fuel line and remove the engine cowling to access the lower unit.
- Drain the lower unit gear oil completely and disconnect the water intake hose if necessary.
- Remove the water pump housing bolts and carefully separate the housing from the lower unit. Note the orientation of all components.
- Remove the old impeller gasket and clean both mating surfaces thoroughly to remove residue, corrosion, or debris.
- Inspect the impeller housing and plate for cracks or wear; replace any damaged components before reassembly.
- Position the new gasket onto the lower housing, ensuring all bolt holes and water passages align correctly.
- Reinstall the impeller (if removed) with proper lubrication, ensuring blades are oriented in the correct rotation direction.
- Carefully seat the water pump housing onto the gasket, aligning dowel pins and bolt holes without shifting the gasket.
- Install housing bolts hand-tight in a crisscross pattern, then torque to manufacturer specifications (typically 7–10 ft-lbs).
- Reconnect all water hoses, refill the lower unit with the correct grade and quantity of gear oil, and check for leaks.
- Reinstall the engine cowling and reconnect the fuel line. Start the engine and verify strong water flow from the tell-tale outlet.
- Run the engine at idle for several minutes and inspect the pump area for any signs of water leakage or abnormal operation.
Troubleshooting & FAQ
Q: How do I confirm this gasket fits my Yamaha or Mariner outboard?
A: Cross-reference your engine's model, horsepower, year, and serial number prefix with the compatibility table above. Verify that your original gasket matches the OEM part number 689-44316-A0.
Q: How often should I replace the impeller gasket?
A: Replace the gasket every time you service or replace the water pump impeller—typically every 2–3 years or 200–300 hours of operation. Reusing old gaskets can cause leaks and cooling system failure.
Q: What are the signs that my water pump gasket is failing?
A: Symptoms include reduced or no water flow from the tell-tale, engine overheating, visible water leaks around the pump housing, or moisture in the lower unit. Inspect and replace the gasket immediately if any of these occur.
Q: Can I reuse the old gasket if it looks intact?
A: No. Gaskets compress and conform to mating surfaces during initial installation and will not seal properly when reused. Always install a new gasket during water pump service.
Q: Is this an OEM or aftermarket part?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
-
Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.