SKU: 36641660560

Serpentine Belt Idler Pulley Set – Fits MerCruiser V6/V8 4.3-6.2L (Replaces 8M6500024, 865598, 864625T)

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Description

Serpentine Belt Idler Pulley Set – Fits MerCruiser V6/V8 4.3-6.2L (Replaces 8M6500024, 865598, 864625T)Serpentine Belt Idler Pulley Set Fits MerCruiser V6 V8 4. 3 6. 2L This serpentine belt idler pulley set is designed for a wide range of MerCruiser V6 and V8 marine engines from 1999 to the present, specifically models equipped with a serpentine belt system and a seawater pump. It is a direct replacement for original equipment parts, ensuring proper fit and function. This kit provides direct replacements for MerCruiser part numbers 8M6500024, 865598

Serpentine Belt Idler Pulley Set – Fits MerCruiser V6/V8 4.3-6.2L

This serpentine belt idler pulley set is designed for a wide range of MerCruiser V6 and V8 marine engines from 1999 to the present, specifically models equipped with a serpentine belt system and a seawater pump. It is a direct replacement for original equipment parts, ensuring proper fit and function.

This kit provides direct replacements for MerCruiser part numbers 8M6500024, 865598 (smooth pulley), and 864625T (grooved pulley), as well as the Sierra aftermarket kit 18-15100.

  • Installation Method: Direct replacement for a straightforward installation.
  • Engine Fuel Type: Compatible with gasoline engines.
  • Complete Kit: Includes both the smooth and grooved idler pulleys required for a full service.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Brand Part Number
MerCruiser 8M6500024
MerCruiser 865598
MerCruiser 864625T
Sierra 18-15100

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Brand Model Rated HP Stroke Years OEM Part No. Notes
MerCruiser Alpha/Bravo 4.3L Various 4-Stroke 1999–Present 8M6500024/865598 (smooth)
864625T (grooved)
Models with seawater pump
MerCruiser Alpha/Bravo 5.0L Various 4-Stroke 1999–Present 8M6500024/865598 (smooth)
864625T (grooved)
Models with seawater pump
MerCruiser Alpha/Bravo 5.7L Various 4-Stroke 1999–Present 8M6500024/865598 (smooth)
864625T (grooved)
Models with seawater pump
MerCruiser Alpha/Bravo 6.2L Various 4-Stroke 1999–Present 8M6500024/865598 (smooth)
864625T (grooved)
Models with seawater pump
MerCruiser Alpha/Bravo 6.3L Various 4-Stroke 1999–Present 8M6500024/865598 (smooth)
864625T (grooved)
Models with seawater pump
MerCruiser MPI 4.3-6.2L Various 4-Stroke 1999–Present 8M6500024/865598 (smooth)
864625T (grooved)
Models with seawater pump

Technical Specifications

Specification Value
Product Type Serpentine Belt Idler Pulley Set
Installation Direct replacement
Fuel Type Gasoline
Dimensions Smooth Pulley: ~3-3/16" (81mm) diameter
Grooved Pulley: ~4-1/4" (108mm) diameter
Other Technical Attributes Includes both smooth and grooved pulleys for complete service

Package Contents

  • 1 x Serpentine Belt (Replaces 57-865615Q03, 862087A1)
  • 1 x Smooth Idler Pulley (Replaces 8M6500024, 865598) - ~3-3/16" diameter
  • 1 x Grooved Idler Pulley (Replaces 864625T) - ~4-1/4" diameter

Installation Guide

  1. Safety First: Disconnect the boat's battery before beginning work.
  2. Relieve Belt Tension: Use a breaker bar or serpentine belt tool on the tensioner pulley to release tension from the belt.
  3. Remove Old Belt: Carefully slide the old serpentine belt off the pulleys.
  4. Remove Old Pulleys: Unbolt and remove both the old smooth and grooved idler pulleys. Note their locations.
  5. Install New Pulleys: Mount the new grooved and smooth pulleys in their correct positions and tighten the bolts to the manufacturer's recommended torque specification.
  6. Route New Belt: Following the engine's belt diagram, route the new serpentine belt around all pulleys.
  7. Apply Tension: Slowly release the tensioner to apply pressure to the new belt, ensuring it is properly seated in all pulley grooves.
  8. Final Check: Reconnect the battery. Start the engine and visually inspect the belt and pulleys to ensure they are running smoothly and quietly.

Troubleshooting & FAQ

Q: How do I know if this pulley set will fit my MerCruiser engine?

A: This set is designed for MerCruiser V6 and V8 engines (4.3L, 5.0L, 5.7L, 6.2L, 6.3L) from 1999 to present that use a serpentine belt and a seawater pump. To guarantee fitment, please check your engine model against the "Compatible Engine Models" table and confirm your OEM part numbers match 8M6500024, 865598, or 864625T.

Q: What are the signs that my idler pulleys need replacement?

A: Common signs of failing idler pulleys include a persistent squealing, chirping, or grinding noise from the engine bay, especially when the engine is running. You may also notice visible wobble in a pulley or find cracks or chips on the pulley surface. A worn pulley can lead to belt slippage or complete failure.

Q: Is there a difference between the smooth and grooved pulley in this kit?

A: Yes, they perform different roles. The grooved pulley is designed to guide the ribbed side of the serpentine belt. The smooth pulley runs along the flat, back side of the belt. This kit includes both distinct pulleys for a complete and correct service.

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 shipping—typically 5–15 days worldwide—and 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 exist—even if your model is listed—do 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 5–15 days.
  • Direct from Manufacturer: Competitive pricing without compromising quality.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 36641660560

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4.1 ★★★★★
Based on 27 reviews
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Verified Purchase
Kim
Los Angeles, US
★★★★★ 5
Great gadget!
This little gadget is a lifesaver! Holds bully sticks perfectly! Buy it! My pup enjoys using it and is easy to hold.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 11, 2026
A
Verified Purchase
Alibill
Fort Morgan, US
★★★★★ 5
It absolutely holds a bully or collagen sticks in place!
This actually works! I was skeptical that it could hold a treat but it does hold my Aussies collagen sticks in place so he doesn’t just try to swallow them. It is pretty heavy too.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 21, 2025
R
R. Reviews
Louisville, US
★★★★★ 4
Solid Build, But Not German Shepherd-Proof
I bought this bully stick holder for my German Shepherd, who is an aggressive chewer and has a talent for demolishing toys in minutes. The design is sturdy, and the material feels genuinely heavy-duty — no issues with cracks or breakage so far. However, the biggest problem I’ve run into is that the bully stick doesn’t always stay securely in place. My dog is strong and smart, and within a few minutes, he can twist or yank the stick loose and start chomping on the whole thing, which defeats the safety purpose. I’ve tried adjusting how I insert the stick, but it doesn’t always hold firm, especially with thinner bully sticks. That said, it does work better with thicker, straight sticks, so I’d recommend it if your pup isn’t quite as determined (or stubborn!) as mine. I still use it under supervision, and it slows him down a bit, but I was hoping for a more secure grip. Great idea and solid quality — just wish it was more GSD-proof.
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Reviewed in the United States on July 13, 2025
R
Verified Purchase
Rita Cooper
Alexandria, US
★★★★★ 5
Totally worth the money!
Love this product! It hold the bully sticks very well!! And it can be a toy!
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Reviewed in the United States on August 28, 2025
G
GLSS
Bozeman, US
★★★★★ 5
Where has this been all our pup's life!?!
WOW, I never even knew something like this existed! As a very loving Mini-Aussi mama I have just been holding those super stinky bully sticks for our pup every time she wants to chew on them for the last 4 years! And I'll admit sometimes if I don't want to hold them that means she doesn't get that kind of treat. And once they get too short to hold, probably about 5-6" I have to throw them out because it just doesn't work well for either of us (or for my fingers which my sweet girl would never mean to bite but sometimes are way to close to the gnawing drooling action for either of our comfort!) This solution is ideal!! The shark twist locks in the stump (or any length bully stick) super tight so that she won't get it to the last tiny end bit to choke on it, but I can still untwist it with just a bit of muscle to get out the last bit once she is done - and she can't. The rubber is very strong and she hasn't damaged it at all even with her strong chewing, clawing and pulling. It's strong/tough enough that it's not a rubber she seems to wants to chew and she stays focused on the bully stick. And I've paid close attention to take it away once she has it down to the point of not having any more bully stick exposed to chew, which does result in some pouting, but it also makes the next time this toy come out all the more fun. She's got great leverage to hold on to the bully stick herself using this holder where she had no leverage before (or used her claw into my hand or my arm as leverage) and it allows her to sit and chew on it next to us calmly, without us being actively involved with holding it for her. We still watch her closely while using it for her own safety, like many things-I don't think I would leave her alone with it if I left the house, but that is probably just me being over-protective. For me this is the food toy find of the year!!! She absolutely loves it and is excited EVERY time I get it out for her to play with. Great product - thank you so much for making something that is made so well and is so study and robust!! Well worth the investment!!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 7, 2025

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