Sierra V-Belt 47-15470 — Marine Inboard Sterndrive
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The Sierra 18-15470 is a cogged marine V-belt designed for selected MerCruiser and OMC inboard and sterndrive accessory-drive systems. High-strength synthetic cords resist stretching and shock-load failure, while the precision-moulded cog profile improves flexibility and allows greater airflow around the belt. Its specially compounded rubber construction provides smooth load transfer and dependable contact with the pulley grooves.
Key Features
- Marine replacement cogged V-belt
- Effective length: 47 inches / 119.4 cm
- Top width: 29/64 inch / 11.5 mm
- High-strength synthetic tension cords
- Low-stretch construction supports consistent performance
- Moulded cogs improve flexibility and cord support
- Open cog profile helps reduce heat buildup
- Rubber edges provide positive, non-slip pulley contact
- Supplied as one replacement belt
Engine Compatibility
Designed for selected Mercury MerCruiser and OMC marine-engine applications that specify a compatible 47-inch V-belt. Depending on the engine configuration, the belt may operate the alternator, circulation pump or another accessory-drive component.
Serial Number Fitment Notice
Confirm the engine model, serial-number range, original belt number and accessory-drive configuration before ordering. Engines with the same displacement can use different belts depending on the pulley arrangement, alternator, power-steering system and production year.
When This Part Needs Replacement
Replace the belt when it shows cracking, glazing, frayed edges, missing cog material, oil contamination or excessive stretching. Squealing, slipping, repeated loss of tension or a belt riding unusually low in the pulley groove can also indicate belt or pulley wear.
Installation Notes
Inspect the pulleys for corrosion, wear, contamination and alignment before installing the replacement belt. Do not force the belt over the pulley flanges. Set belt tension according to the engine manufacturer's specification, rotate the drive by hand to confirm correct seating and recheck the tension after the initial operating period.
Alternate / Superseded Part Numbers
- Sierra part number: 18-15470
- Supplier or catalogue reference: 47-15470
- Mercury MerCruiser: 57-78200
- Mercury MerCruiser: 57-78200A1
- Mercury Quicksilver: 57-78200Q1
- OMC: 0509309
- Redline: RL15470
- UPC: 030999566591
Parts Desk Insights
Best use case: This belt is the right choice for pre-season service and routine maintenance on MerCruiser and OMC inboard and sterndrive boats. If your engine specifies OEM belt numbers 57-78200, 57-78200A1, 57-78200Q1 or OMC 0509309, this is the direct replacement to have ready before launch. It also makes a practical onboard spare for extended cruising — a belt failure can simultaneously take out raw water cooling and battery charging.
Belt length alone is not enough to confirm fitment. Matching the original part number, belt width and pulley arrangement helps prevent slipping, overheating and premature accessory-drive wear. Always verify the OEM belt number and pulley configuration before ordering.
For a complete cooling system service, pair this belt with a raw water pump impeller replacement. See the PCM Impeller Kit RP061017 and PCM / Crusader RP061022 Raw Water Pump Impeller for compatible options. Need a different belt size? Browse the Sierra V-Belt 47-15400, Sierra V-Belt 47-15410, Sierra V-Belt 47-15440, Sierra V-Belt 47-15450, Sierra V-Belt 47-15455, Sierra V-Belt 47-15460, and Sierra V-Belt 47-15550 for other sizes in the same series.
Shop all Engine Parts & Maintenance or browse Propulsion & Powertrain for related components.
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.