Sierra 3070 Yamaha Impeller
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The Sierra 3070 (18-3070) Impeller is a six-blade replacement lower-unit water pump impeller for select Yamaha two-stroke outboards. It rotates inside the water pump housing to draw cooling water through the gearcase and circulate it through the engine. Replaces Yamaha OEM impeller 688-44352-03-00. Included in Sierra water pump kits 18-3370 and 18-3371.
Parts Desk Insight — Best Use
Note that 47-3070 can resemble a Mercury OEM impeller number but is the Land ‘N’ Sea distributor SKU for Sierra 18-3070. Confirm that the Yamaha water pump diagram calls for 688-44352-03-00 before ordering — especially on 60–90 HP engines where Yamaha used several different pump designs across model years. The 688-series impeller spans a wide range of two-stroke models (1984–2009), so production year and full model code are both required for a reliable match.
Replace every 2–3 seasons or 200 hours regardless of visible wear. Sand, silt, dry operation, and extended storage can harden or damage the flexible blades, reducing cooling-water delivery before any visible external sign of failure.
Key Specifications
- Sierra part number: 18-3070
- Six flexible impeller blades
- Fits select Yamaha two-stroke 60–90 HP outboards (1984–2009)
- Included in Sierra water pump kits 18-3370 and 18-3371
- Impeller only — housing, wear plate, key, and seals not included
- UPC: 030999315229
Engine Compatibility
Documented Yamaha applications:
- 60 HP: 2004–2005
- 70 HP: 2004–2009
- C75: 1994–1999
- E75: 1995–2000
- P75: 1996–1999
- C80: 1997
- C85: 1991–1996
- CV85: 1989–1990
- 90 HP: 1984–2009
- 90 Jet: 1986–1989
- B90: 1997–1999
- C90: 1997–2001
Always confirm by complete engine model code, production year, serial number, and OEM water pump parts diagram showing 688-44352-03-00.
Alternate Part Numbers
- Sierra: 18-3070 / 118-3070
- Yamaha: 688-44352-03-00 / 688-44352-03
- GLM Marine: 89920
- Mallory Marine: 9-45603, 9-45603-10
- Aqua Power: 2006
Installation Notes
Lower-unit removal is required to access the water pump assembly. During service: inspect the pump housing, stainless cup, wear plate, key, and seals; remove any broken impeller fragments from cooling passages; lubricate the new impeller with clean soapy water or approved assembly lubricant; rotate the driveshaft in its normal operating direction while seating the housing over the blades. Confirm strong cooling-water telltale flow before operating under load. Never operate the outboard without an adequate cooling-water supply.
Compatible Yamaha Water Pump Kits
- Sierra 3371 Yamaha Water Pump Repair Kit
- Sierra 3433 Yamaha Water Pump Repair Kit
- Sierra 3434 Yamaha Water Pump Repair Kit
- Sierra 3442 Yamaha Water Pump Repair Kit
Related Yamaha Impellers
- Sierra 3071 (18-3071) Yamaha Impeller – 115–250HP
- Sierra 3042 (18-3042) Yamaha Impeller – F75/F80/F90/F100
- Sierra 3074 (18-3074) Yamaha/Mercury/Mariner Impeller – 9.9–15HP
- Sierra 3073 (18-3073) Yamaha/Mercury/Mariner Impeller – 4–5HP
- Sierra Impeller 18-3086 – Yamaha Outboard Water Pump Replacement
Always confirm fitment against your Yamaha service manual and full model/year before ordering.
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.