Sierra 18-3069 Yamaha/Mercury/Mariner Impeller
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The Sierra 18-3069 is a six-blade replacement lower-unit water pump impeller for compatible Mercury, Mariner and Yamaha outboards. It rotates inside the pump housing to draw cooling water through the gearcase and circulate it through the engine. The 47-3069 number is a distributor SKU for Sierra part 18-3069.
Key Features
- Sierra manufacturer part number: 18-3069
- Distributor SKU: 47-3069
- Six flexible impeller blades
- Compatible with select Mercury, Mariner and Yamaha outboards
- Replaces Mercury/Mariner 47-81423M, 47-82824M and 47-97108M
- Replaces Yamaha 697-44352-00-00 and 6H3-44352-00-00
- Included in multiple Sierra water pump kits, including 18-3425, 18-3434, 18-3415, 18-3464, 18-3465, 18-3466, 18-3494 and 18-3461
- UPC: 030999315212
Engine Compatibility
Documented Yamaha applications include select:
- 40 HP outboards
- 48 HP outboards
- 50 HP outboards
- 55 HP outboards
- 60 HP outboards
- 70 HP outboards
- F50 and T50 four-stroke models
- F60 models from approximately 2002–2017
- T60 models from approximately 2003–2017
- F70A models from approximately 2010–2017
Mercury and Mariner compatibility is tied to water pump assemblies using OEM impeller numbers 47-81423M, 47-82824M or 47-97108M. These references are commonly associated with select 48, 55 and 60 HP outboards, but exact model and serial-number verification is required.
Serial Number Fitment Notice
Do not select this impeller by horsepower alone. Mercury, Mariner and Yamaha used different water pump assemblies across engines with similar horsepower ratings.
Before ordering, confirm:
- Complete engine model and serial number
- Production year
- Gearcase and water pump configuration
- Original impeller number
- Mercury reference 47-81423M, 47-82824M or 47-97108M
- Yamaha reference 697-44352-00-00 or 6H3-44352-00-00
- Impeller bore and drive-key configuration
The original water pump parts diagram provides the safest fitment confirmation.
When This Part Needs Replacement
Replace the impeller if:
- Cooling-water flow becomes weak or intermittent
- The engine begins operating hotter than normal
- An overheat warning activates
- The blades are cracked, torn, stiff or permanently bent
- Rubber fragments are missing
- The centre hub slips inside the impeller
- The engine has been operated without cooling water
- The motor has operated regularly in sandy or silty conditions
- The recommended preventive-maintenance interval has been reached
A worn impeller may continue rotating while no longer delivering enough water to cool the engine safely.
Installation Notes
Lower-unit removal is normally required to access the water pump assembly. During service:
- Disconnect the ignition and battery where applicable
- Follow the correct shift-linkage and lower-unit removal procedure
- Inspect the pump housing, cup, wear plate, key, seals and driveshaft
- Remove broken impeller fragments from the cooling passages
- Lubricate the impeller with clean soapy water or approved assembly lubricant
- Position the drive key correctly
- Rotate the driveshaft in its normal operating direction while lowering the housing over the blades
- Replace worn gaskets, O-rings and pump components
- Reinstall the lower unit according to the engine service manual
- Confirm strong cooling-water flow before operating under load
Never operate the outboard without an adequate cooling-water supply.
Alternate/Superseded Part Numbers
- Sierra: 18-3069
- Distributor SKU: 47-3069
- Sierra catalogue reference: 118-3069
- Mercury/Mariner: 47-81423M
- Mercury/Mariner: 47-82824M
- Mercury/Mariner: 47-97108M
- Mercury shortened references: 81423M, 82824M and 97108M
- Yamaha: 697-44352-00-00
- Yamaha: 6H3-44352-00-00
- GLM Marine: 89910
- Mallory Marine: 9-45602
- Mallory Marine: 9-45602-10
- UPC: 030999315212
Parts Desk Insight
The 47-3069 number can look like a Mercury OEM number, but it is the distributor SKU for Sierra 18-3069. Because this impeller crosses between Mercury/Mariner and Yamaha applications, matching the original OEM number is more reliable than ordering by horsepower alone.
Compatible & Related Products
Other Sierra impellers and water pump kits for Yamaha and Mercury/Mariner outboards:
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 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 — 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 — 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.