Sierra Marine Water Pump Kit 18-48317 - Complete Cooling System Rebuild
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Sierra Marine Complete Water Pump Kit 18-48317 ā Mercury / Tohatsu 8-9.9HP 4-Stroke Cooling System Rebuild
The Sierra 18-48317 Complete Water Pump Kit is a full-service rebuild solution designed to restore proper cooling performance in small horsepower 4-stroke outboards. This kit includes all critical wear components required to service the water pump assembly, ensuring reliable water flow and preventing overheating.
Built to meet or exceed OEM specifications, this kit is a direct aftermarket replacement for Mercury, Nissan, and Tohatsu outboards using the 209cc platform. Ideal for scheduled maintenance or correcting weak telltale flow, overheating, or impeller failure.
This is a complete rebuild kit, eliminating the need to source individual gaskets, seals, or internal components.
Key Features
- Complete water pump rebuild kit (impeller, gaskets, seals, wear components)
- Restores proper engine cooling water flow
- Direct OEM replacement fit and performance
- Meets or exceeds manufacturer specifications
- Sierra limited lifetime warranty
- Designed for small 4-stroke outboards (209cc platform)
Engine Compatibility
Mercury / Mariner Outboards
- 8 HP 4-Stroke (209cc)
- 9.9 HP 4-Stroke (209cc)
- Serial Range: R042475 & newer
Nissan / Tohatsu Outboards
- F8 (4-stroke)
- F9.8 (4-stroke)
These engines share the same 209cc block and cooling system design, making this kit cross-compatible across all listed models.
Serial Number Fitment Notice
Fitment is based on engine serial number and production range. Mercury models must be R042475 or newer.
ā ļø Always confirm fitment using your engine serial number before ordering, especially for early or transitional model years.
When This Part Needs Replacement
Replace the water pump kit if you experience:
- Weak or no telltale (pee stream)
- Engine overheating alarms
- Reduced cooling efficiency at idle
- Impeller wear or deformation (common every 2ā3 seasons)
- Saltwater corrosion inside pump housing
Routine service interval: every 100 hours or annually (especially in saltwater use)
Installation Notes
- Install with marine grease on impeller vanes
- Ensure correct impeller rotation direction during install
- Inspect housing and wear plate for scoring (replace if needed)
- Torque fasteners to OEM spec
- Prime system with water before initial startup
Professional installation recommended if unfamiliar with lower unit service.
Alternate / Superseded Part Numbers
OEM / Cross References:
- Mercury Marine: 46-803750A03
- Nissan / Tohatsu: 3B2-87322-0, 3B2873221M, 3B2873222M
- Mallory: 9-48317
Shipping
Shipping: Ships same or next day for fast Canada wide shipping. ā
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3ā4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us ā and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity ā and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.