Sierra Marine V-Belt 18-15440 | 44 in. / 111.8 cm × 29/64 in. / 11.5 mm
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Sierra Marine V-Belt 18-15440 — 44 in. / 111.8 cm × 29/64 in. / 11.5 mm
The Sierra 18-15440 is a cogged marine V-belt designed for the accessory-drive system on select MerCruiser and OMC inboard and sterndrive engines. With an effective length of 44 in. / 111.8 cm and a top width of 29/64 in. / 11.5 mm, it drives the alternator and raw water pump on compatible 1975–1977 applications. Built with high-strength synthetic cords, precision-moulded cogs, and positive-grip rubber sidewalls for stable power transfer and long service life in a marine environment.
Part Information
- Part Number (Sierra): 18-15440
- SKU: 47-15440
- Brand: Sierra
- Official Product Type: Cogged Marine V-Belt
- UPC: 030999566539
- System: Accessory Drive (Alternator / Raw Water Pump)
- Effective Length: 44 in. / 111.8 cm
- Top Width: 29/64 in. / 11.5 mm
Cross-Reference Part Numbers
- Mercury / MerCruiser: 57-45856, 57-49213A1, 57-93658Q
- OMC: 311046
- Mallory: 9-55006
Compatible Applications
- MerCruiser 233 HP — select 1975–1977 models
- MerCruiser 233 MIE — select 1975–1976 models
- Additional MerCruiser accessory-drive configurations using a 44 in. belt with a 5.5 in. / 139.7 mm water-pump pulley
- OMC applications cross-referencing part number 311046
Fitment Note: Before ordering, confirm your engine model, serial number, existing OEM belt number, water-pump pulley diameter, and required belt length. Similar MerCruiser engines may use 46 in., 47 in., or other belt lengths depending on pulley and accessory configuration. When in doubt, measure the belt you are replacing.
Service Interval
- Inspect at every spring commissioning and 100-hour service
- Replace when cracks appear between cogs, edges fray, belt glazes or hardens, or when squealing and slippage develop
- Replace immediately if oil or coolant contamination is present on the belt
- Keeping a spare belt onboard is recommended for longer passages
Technical Notes
- Inspect pulley grooves for wear or corrosion before installation
- Confirm correct belt routing and alternator/water-pump alignment
- Set tension to engine manufacturer’s specification — do not over-tension
- Do not force the belt over pulley flanges with sharp tools
- Rotate the drive through one full revolution after installation to confirm proper seating in every pulley
Parts Desk Insights
Best Use: The 18-15440 is most commonly needed during spring commissioning or pre-season service on mid-1970s MerCruiser 233 HP and 233 MIE sterndrives. If the existing belt shows any cracking, glazing, or age-related hardening, replace it before the season starts — a broken accessory belt will take out both your charging system and raw water cooling simultaneously.
Common Issues: The most frequent fitment error with this belt is confusing it with the 46 in. or 47 in. versions used on other MerCruiser configurations. Always verify pulley diameter (5.5 in. / 139.7 mm for this application) and cross-reference with OEM number 57-49213A1 to confirm you have the right length before installation.
Related Parts
- Sierra Marine V-Belt 18-15470 — 47 in. / 119.4 cm — next size up in the same cogged belt series
- Sierra Marine V-Belt 18-15480 — 48 in. / 121.9 cm — 48-inch variant for other MerCruiser configurations
- Sierra V-Belt 47-15400 — shorter belt in the same accessory-drive series
- Sierra V-Belt 47-15455 — 44.5 in. intermediate size
- Sierra V-Belt 47-15450 — 45 in. variant
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 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.