Description
Belt Tensioner PulleyFits MerCruiser 4.3-8.1L Engines (Replaces 8M6500024, 865598)
This belt tensioner pulley is designed for a wide range of MerCruiser inboard and stern drive engines, including 4.3L, 5.0L, 5.7L, 5.8L, 6.2L, and 8.1L V6/V8 models from 19962025. It is also compatible with General Motors 262 CID V6 (4.3L) and GM V8 small block 5.0L & 5.7L engine blocks.
This is a direct replacement for Mercury part numbers 8M6500024, 818382, and 865598. It also replaces aftermarket parts from Sierra, Heurofosh, and YiheoZux.
- Installation Method: Direct replacement
- Pulley Type: Smooth, flat surface (no grooves)
- Housing Material: High-strength thermal resin
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury | 8M6500024 |
| Mercury | 818382 |
| Mercury | 865598 |
| Sierra | 710-8M6500024 |
| Heurofosh | 865598 |
| YiheoZux | 8M6500024 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, heres a guide to help you identify your engines serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
Confirm your engine model/year in the table below.
MerCruiser/Mercury
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 4.3L | V6 | 4-Stroke | 19962025 | 8M6500024 | |
| MerCruiser | 5.0L | V8 | 4-Stroke | 19962025 | 8M6500024 | |
| MerCruiser | 5.7L | V8 | 4-Stroke | 19962025 | 8M6500024 | |
| MerCruiser | 5.8L | V8 | 4-Stroke | 19962025 | 8M6500024 | |
| MerCruiser | 6.2L | V8 | 4-Stroke | 19962025 | 8M6500024 | |
| MerCruiser | 8.1L | V8 | 4-Stroke | 19962025 | 8M6500024 | |
| MerCruiser | 454 | 7.4L V8 | 4-Stroke | 19962025 | 8M6500024 | For engines with V-Belt driven raw water pump with fuel pump |
General Motors
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| GM | 262 CID | V6, 4.3L | 4-Stroke | 865598 | Engine block parts |
| GM | Small Block | V8, 5.0 & 5.7L | 4-Stroke | 865598 | Engine block parts |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Serpentine Belt Tensioner Pulley |
| Installation | Direct replacement |
| Housing Material | Thermal resin |
| Housing Color | Black |
| Dimensions | Diameter: 3″ (79.4 mm), Bearing diameter: ” (15.9 mm) |
| Fitting Type | Direct mount |
| Warranty | 1 year (varies by seller) |
| Other Technical Attributes | Smooth, flat pulley surface (no grooves), bearing is molded into the pulley |
Package Contents
- 1 x Belt Tensioner Pulley (8M6500024/865598/818382)
Installation Guide
Always consult your engines service manual before beginning work. The general steps for replacement are as follows:
- Disconnect the Battery: Ensure the engine is off and disconnect the negative battery terminal for safety.
- Locate the Tensioner Assembly: Find the serpentine belt and trace it to the spring-loaded tensioner assembly where the pulley is mounted.
- Release Belt Tension: Use a socket wrench or serpentine belt tool on the tensioner arm bolt to release tension and carefully slip the belt off the pulley.
- Remove the Old Pulley: Unbolt the center bolt holding the old pulley to the tensioner arm and remove it.
- Install the New Pulley: Position the new pulley, ensuring it is correctly aligned, and tighten the center bolt to the manufacturer’s specified torque.
- Reinstall the Serpentine Belt: Route the belt correctly around all pulleys according to your engine’s diagram. Release the tensioner arm to tighten the belt.
- Final Check: Reconnect the battery terminal. Start the engine and listen for any unusual noises and visually confirm the belt is tracking correctly on the new pulley.
Troubleshooting & FAQ
Q: How do I confirm this fits my engine?
A: The most reliable method is to match your existing part number to those listed in our Part Number Cross-Reference table. Additionally, check your engine model and year against the Compatible Engine Models list. Visual comparison with our product photos is also recommended.
Q: What are the common signs of a failing tensioner pulley?
A: Symptoms of a bad pulley include a persistent squealing or grinding noise from the engine bay, visible wobbling of the pulley while the engine is running, and premature or uneven wear on the serpentine belt.
Q: What is the difference between this and the OEM part?
A: This is an aftermarket pulley made from high-strength thermal resin, similar to the original. The bearing is molded directly into the pulley for durability. It is designed to meet or exceed OEM specifications for fit and performance.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shippingtypically 515 days worldwideand standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies existeven if your model is listeddo not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
- Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
- Fast Global Shipping: Free delivery worldwide in 515 days.
- Direct from Manufacturer: Competitive pricing without compromising quality.
