861578 Power Steering Pump Pulley for MerCruiser 4.3L 5.0L 5.7L 6.2L V6 V8 | JLM Marine

Power Steering Pump Pulley 861578 – Fits MerCruiser 4.3L 5.0L 5.7L 6.2L V6 V8 Engines

This power steering pump pulley is engineered for MerCruiser 4.3L, 5.0L, 5.7L, and 6.2L V6 and V8 engines, delivering reliable performance for serpentine belt-driven steering systems. Designed as a direct replacement for OEM part number 861578, this pulley ensures proper belt alignment and smooth power steering operation across a wide range of MerCruiser inboard and sterndrive applications.

This aftermarket pulley directly replaces Mercury MerCruiser 861578 and aftermarket equivalent Sierra 18-8297, providing a cost-effective solution without compromising quality or fit.

• Compatible with MerCruiser serpentine belt systems on V6 and V8 engines
• Direct replacement for OEM 861578 and Sierra 18-8297
• Essential component for maintaining proper power steering function

Part Number Cross-Reference

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

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.

Technical Specifications

Package Contents

• 1 × Power Steering Pump Pulley (861578)

Installation Guide

1. Disconnect the negative battery cable to prevent accidental starts during installation.
2. Relieve tension on the serpentine belt using the appropriate tensioner tool and remove the belt from the power steering pump pulley.
3. Secure the power steering pump shaft to prevent rotation, then remove the retaining bolt or nut from the old pulley.
4. Carefully pull the old pulley off the pump shaft; note any shims or spacers and their positions.
5. Clean the pump shaft surface to remove any debris or residue before installing the new pulley.
6. Install any shims or spacers in their original positions, then slide the new pulley onto the shaft.
7. Thread the retaining bolt or nut and tighten to the manufacturer's specified torque (consult your service manual).
8. Reinstall the serpentine belt, ensuring proper routing and alignment across all pulleys.
9. Verify that the belt tension is correct and the pulley spins freely without wobble or misalignment.
10. Reconnect the negative battery cable and start the engine to confirm proper operation.
11. Check for unusual noise or vibration and verify that power steering function is restored.
12. Inspect the belt and pulley after the first few hours of operation to ensure everything remains properly seated.

Troubleshooting & FAQ

Q: How do I confirm this pulley fits my MerCruiser engine?
A: Verify your engine is a 4.3L, 5.0L, 5.7L, or 6.2L V6/V8 with a serpentine belt system, and cross-reference your current part number with 861578 or Sierra 18-8297. If your original pulley matches these specifications, this replacement will fit.

Q: What are the signs that my power steering pump pulley needs replacement?
A: Common symptoms include squealing or chirping noises from the belt area, visible cracks or damage to the pulley grooves, belt slippage, or intermittent power steering function. A wobbling pulley or excessive wear on the serpentine belt also indicates replacement is needed.

Q: Can I install this pulley myself or do I need a professional?
A: Installation requires basic mechanical skills and tools, including a method to secure the pump shaft and a torque wrench. If you're comfortable working with serpentine belt systems and have the proper tools, DIY installation is feasible. Professional installation is recommended if you're uncertain about proper torque specs or belt alignment.

Q: Will this aftermarket pulley perform the same as the OEM part?
A: Yes, this pulley is manufactured to OEM specifications using comparable-grade materials, ensuring proper fit and performance. While it's an aftermarket replacement (not an OEM component), it's produced in an ISO9002-certified facility and inspected for quality to meet the same functional standards.

Q: What's the difference between OEM and 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.