Sierra V-Belt 47-15400 — Marine Inboard Sterndrive
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The Sierra 18-15400 is a cogged marine V-belt designed for compatible MerCruiser, Mercury Marine and OMC engine accessory-drive systems. Its high-strength synthetic cords resist shock loading and stretching, while the moulded cog profile improves flexibility and increases cooling airflow. Specially compounded rubber helps transfer load evenly and maintain dependable contact with the pulley grooves.
Key Features
- Marine replacement cogged V-belt
- Effective length: 40 inches / 101.6 cm
- Top width: 29/64 inch / 11.5 mm
- High-strength, low-stretch synthetic cords
- Resists shock-load failure
- Moulded cogs improve belt flexibility
- Open cog profile helps reduce heat buildup
- Special rubber compression section distributes load evenly
- Rubber edges maintain positive pulley contact
- Supplied as one replacement belt
Engine Compatibility
Designed for selected MerCruiser sterndrive, Mercury Marine and OMC marine-engine applications that specify a corresponding 40-inch belt. Common applications include certain four-cylinder marine engines and accessory-drive arrangements using the listed OEM belt numbers.
Serial Number Fitment Notice
Confirm the engine model, serial-number range, original belt number and accessory-drive configuration before ordering. Engines of the same displacement may use different belts depending on the alternator, power-steering system, pulley arrangement and production year.
When This Part Needs Replacement
Replace the belt when it becomes cracked, glazed, frayed, oil-soaked or excessively stretched. Squealing, slipping, repeated loss of tension or a belt riding unusually low in the pulley groove can also indicate wear, pulley misalignment or an incorrect belt profile.
Installation Notes
Inspect the pulleys for corrosion, wear, contamination and alignment before installing the new 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 correct seating and recheck the tension after the initial operating period.
Alternate / Superseded Part Numbers
- Sierra part number: 18-15400
- Supplier or catalogue reference: 47-15400
- Mercury Marine: 57-32850
- MerCruiser: 57-69143
- MerCruiser: 57-69143Q
- MerCruiser: 57-69143T
- OMC/Johnson/Evinrude: 311606
- OMC: 0311606
- Related OMC reference: 0509301
- Related Volvo Penta reference: 3852106
- UPC: 030999566454
Parts Desk Insights
Best use case: This belt is the go-to replacement for pre-season service and routine maintenance on MerCruiser sterndrive, Mercury Marine and OMC inboard boats. If your engine specifies OEM belt numbers 57-32850, 57-69143 or 311606, this is the direct replacement to have ready before launch. It also makes a smart onboard spare for extended cruising — a belt failure can simultaneously take out raw water cooling and battery charging.
A belt that is close in length can still be wrong for the pulley system. Matching the original part number, belt width and accessory-drive arrangement helps prevent slipping, overheating and premature 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 47-15410, Sierra V-Belt 47-15440, Sierra V-Belt 47-15450, Sierra V-Belt 47-15455, 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.