Serpentine Belt for MerCruiser 4.3L V6 and 5.0L–6.2L V8 Engines
Serpentine Belt for MerCruiser 4.3L V6 and 5.0L–6.2L V8 Engines is backordered and will ship as soon as it is back in stock.
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Serpentine Belt for MerCruiser 4.3L V6 and 5.0L–6.2L V8 Engines
Serpentine Belt for MerCruiser 4.3L V6 and 5.0L–6.2L V8 Engines is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket serpentine belt is designed for selected MerCruiser stern-drive and out-drive applications, including 4.3L V6 engines rated at 155–205 HP and 5.0L–6.2L V8 engines rated at 180–300 HP. It is listed for 1998–2009 MerCruiser applications using Alpha Gen II or Bravo drives, as well as compatible GM and MIE marine engines.
Use the engine model, drive type, year, serial number, belt routing, and original belt dimensions to confirm fitment before ordering. Application details can vary between engines with similar displacement.
- Single serpentine belt for marine engine accessory drive systems.
- Designed for selected MerCruiser Alpha Gen II and Bravo drive applications.
- Aftermarket replacement for the listed Mercury/MerCruiser and Sierra reference numbers.
- Nominal belt width: 13/16 inch; nominal length: 105 inches.
Part Number Matrix
The following numbers are reference and interchange identifiers associated with this belt. They are not the seller's internal product identifier.
| Brand or source | Reference number |
|---|---|
| Mercury / MerCruiser | 57-8638764 |
| Mercury / MerCruiser | 57-865615Q04 |
| Mercury / MerCruiser | 57-862086 |
| Mercury / MerCruiser | 57-8620861 |
| Mercury / MerCruiser | 57-862086A1 |
| Mercury / MerCruiser | 57-865615004 |
| Mercury / MerCruiser | 865615004 |
| Mercury / MerCruiser | 8638764 |
| Sierra | 18-15101 |
Engine and Application Compatibility
The company application listing covers the following engine and drive ranges for 1998–2009. Confirm the complete engine and serial-number combination before purchase; displacement alone does not establish fitment.
| Engine family | Displacement | Configuration | Rated horsepower | Years | Drive or application |
|---|---|---|---|---|---|
| MerCruiser | 4.3L | V6 | 155–205 HP | 1998–2009 | Alpha Gen II or Bravo drive |
| MerCruiser | 5.0L–6.2L | V8 | 180–300 HP | 1998–2009 | Alpha Gen II or Bravo drive |
| GM and MIE marine engines | 4.3L V6 and 5.0L–6.2L V8 applications | As applicable | Within the listed application range | 1998–2009 | Verify belt routing and original reference number |
Important: The exact belt routing and accessory arrangement may depend on the drive, power-steering equipment, alternator position, cooling configuration, and serial-number range. Compare the removed belt and consult the engine service information when necessary.
Technical Specifications
- Product type
- Serpentine belt
- Quantity
- 1 belt
- Nominal width
- 13/16 inch
- Nominal length
- 105 inches
- Application
- Selected MerCruiser stern-drive and out-drive systems, including Alpha Gen II and Bravo drive applications
- Engine range
- 4.3L V6, 155–205 HP; 5.0L–6.2L V8, 180–300 HP
- Listed model years
- 1998–2009
- Replacement type
- Aftermarket replacement belt
What's in the Box
- 1 × serpentine belt
Installation Notes
- Safety first: Switch off the engine, remove the ignition key, and disconnect the battery according to the boat and engine manufacturer's safety procedures.
- Document the routing: Photograph or diagram the existing belt path before removal. Do not rely on memory alone.
- Release belt tension: If the engine is equipped with an automatic tensioner, use the correct tool to release tension. If it uses an adjustable accessory mount, follow the applicable service procedure.
- Inspect related components: Check pulleys, tensioners, idlers, bearings, and accessory mounts for damage, seizure, contamination, or misalignment.
- Install the belt: Route the belt around the correct pulleys without twisting it. Ensure every rib is fully seated in the pulley grooves.
- Set and verify tension: Apply the manufacturer's specified tension where adjustment is required. Rotate the engine by hand as appropriate and recheck alignment before starting.
- Final check: Reconnect the battery, start the engine briefly in a safe, ventilated area, and confirm that the belt tracks smoothly without squealing, rubbing, or walking off a pulley.
Maintenance and FAQ
How do I confirm that this belt fits my engine?
Check the engine displacement, horsepower, model year, drive type, serial number, original belt reference, belt width, and belt length. Also compare the routing and accessory layout. A similar engine displacement does not by itself confirm compatibility.
What are the signs of a worn serpentine belt?
Inspect for cracking, fraying, glazing, missing ribs, oil contamination, uneven wear, looseness, or rib separation. Squealing, chirping, belt dust, and inconsistent accessory operation can also indicate belt or pulley problems.
Is this an OEM Mercury or MerCruiser belt?
No. This is an aftermarket replacement belt listed against the Mercury/MerCruiser and Sierra reference numbers shown above. Mercury and MerCruiser are trademarks of their respective owners.
Does this listing include an idler pulley or tensioner?
No. This listing includes one serpentine belt only. An idler pulley, tensioner, and other accessories are not included.
When should the belt be replaced?
Inspect the belt during routine engine maintenance and replace it when wear, contamination, damage, abnormal noise, or loss of tension is found. Follow the engine manufacturer's maintenance recommendations for inspection intervals.
Can I install this belt without checking the serial number?
It is not recommended. The listed engine families can use different belt arrangements depending on drive, accessory, and serial-number conditions. Verify the complete application before installation.
Safety and Important Information
- Verify the original belt number, dimensions, routing, engine serial number, drive type, and accessory configuration before ordering.
- Do not operate the engine with a misaligned, damaged, contaminated, or incorrectly tensioned belt.
- Disconnect the battery and keep hands, clothing, and tools away from moving pulleys during installation and testing.
- Professional installation is recommended when the belt routing or tensioning system is unfamiliar.
About Sea Sierra
- Marine-focused parts: We supply replacement components for recreational and commercial marine applications.
- Application-conscious listings: We provide reference numbers and fitment information to help customers compare their original parts.
- Global fulfillment: Standard and expedited delivery options are available where supported at checkout.
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