Sierra V-Belt 47-15480 — Marine Inboard Sterndrive
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The Sierra 18-15480 is a cogged marine V-belt designed for selected Mercury MerCruiser inboard and sterndrive accessory-drive systems. High-strength synthetic cords provide low-stretch performance and resistance to shock loading, while the precision-moulded cog profile improves flexibility and promotes airflow to reduce heat buildup. Specially compounded rubber transfers drive loads evenly and maintains dependable contact with the pulley grooves.
Key Features
- Marine replacement cogged V-belt
- Effective length: 48 inches / 121.9 cm
- Top width: 29/64 inch / 11.5 mm
- High-strength, low-stretch synthetic cords
- Moulded cogs improve flexibility and cord support
- Open cog profile promotes cooling airflow
- Rubber edges maintain positive pulley contact
- Supplied as one replacement belt
Engine Compatibility
Designed for selected Mercury MerCruiser V-belt accessory-drive systems, including certain 5.7L, 7.4L and 8.2L V8 applications. Depending on the engine configuration, the belt may drive the alternator and engine circulation pump. This is a conventional V-belt and is not intended for engines equipped with a serpentine-belt system.
Serial Number Fitment Notice
Confirm the engine model, serial-number range, original belt number and accessory-drive arrangement before ordering. MerCruiser engines of the same displacement may use different belts depending on production year, cooling system, pulley arrangement and whether the engine uses a V-belt or serpentine drive.
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 wear, pulley wear or incorrect fitment.
Installation Notes
Inspect the pulleys for corrosion, contamination, wear and misalignment before installing the replacement belt. Do not force the belt over the pulley flanges. Set the tension according to the engine manufacturer's specification, rotate the drive by hand to confirm proper seating and recheck the tension after the initial operating period.
Alternate / Superseded Part Numbers
- Sierra part number: 18-15480
- Supplier or catalogue reference: 47-15480
- Mercury MerCruiser: 57-48122
- Mercury Quicksilver: 57-48122Q
- Mallory: 9-55003
- GLM: 89440
- Related OMC reference: 0509295
- UPC: 030999566614
Parts Desk Insights
Best use case: This belt is the right choice for pre-season service and routine maintenance on MerCruiser 5.7L, 7.4L and 8.2L V8 inboard and sterndrive boats running a conventional V-belt accessory drive. If your engine specifies OEM belt numbers 57-48122 or 57-48122Q, this is the direct replacement to have ready before launch. It also makes a practical onboard spare — a belt failure can simultaneously take out raw water cooling and battery charging.
A 48-inch belt is not automatically the correct belt. Match the original part number, belt width and pulley arrangement before ordering, especially on older engines that may have been modified or repowered. If your engine has been converted to a serpentine-belt system, this belt does not apply.
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, Sierra V-Belt 47-15470, 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.