66M-46241-00 Timing Belt for Mercury Yamaha Tohatsu Nissan MFS9.9A MFS9.9B MFS9.9B2 MFS9.9C MFS15A MFS15B MFS15B2 MFS15C MFS18B MFS18B2 MFS20C NSF9.9A NSF9.9B NSF9.9B2 NSF9.9C NSF15A NSF15B NSF15B2 NSF15C NSF18B NSF18B2 NSF20C | JLM Marine

Timing Belt for Mercury Yamaha Tohatsu Nissan MFS9.9A MFS9.9B MFS9.9B2 MFS9.9C MFS15A MFS15B MFS15B2 MFS15C MFS18B MFS18B2 MFS20C NSF9.9A NSF9.9B NSF9.9B2 NSF9.9C NSF15A NSF15B NSF15B2 NSF15C NSF18B NSF18B2 NSF20C

This replacement timing belt is designed for Yamaha, Tohatsu, Nissan, and Mercury 4-stroke outboard engines ranging from 9.9 HP to 20 HP. It fits a wide range of MFS and NSF series models from 2002 to 2014, ensuring compatibility across multiple years and configurations. Engineered to meet OEM specifications, this timing belt ensures proper camshaft and oil pump synchronization for reliable engine performance.

Direct Replacements: Mercury 57-835392Q, Yamaha 66M-46241-00, Sierra 18-15147, Tohatsu 3H8-10061-0. This belt replaces multiple OEM part numbers across Mercury, Yamaha, Tohatsu, and Nissan brands, providing broad coverage for various 4-stroke outboard models up to 2008 and beyond.

• Fits Mercury & Mariner 9.9HP & 15HP 4-stroke outboards up to 2008
• Compatible with Tohatsu and Nissan MFS/NSF series engines for camshaft and oil pump timing
• Direct replacement for multiple OEM part numbers ensuring easy cross-reference

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 Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 × Timing Belt (66M-46241-00)

Installation Guide

1. Preparation: Disconnect the battery and ensure the engine is cool. Gather necessary tools including socket wrenches, screwdrivers, and a torque wrench.
2. Access the Timing Belt: Remove the engine cover and any components obstructing access to the timing belt housing. Refer to your engine's service manual for specific disassembly steps.
3. Align Timing Marks: Rotate the crankshaft to position the timing marks on the crankshaft and camshaft pulleys at their alignment points. This ensures correct valve timing during reassembly.
4. Remove Old Belt: Loosen the tensioner and carefully remove the old timing belt from the pulleys. Inspect the pulleys and tensioner for wear or damage.
5. Install New Belt: Route the new timing belt over the crankshaft pulley, camshaft pulley, and tensioner following the correct rotation direction. Ensure the belt seats properly in all pulley grooves.
6. Tension the Belt: Adjust the tensioner according to manufacturer specifications to achieve proper belt tension. Verify that timing marks remain aligned after tensioning.
7. Verify Timing: Manually rotate the crankshaft two full revolutions and recheck all timing marks. Confirm they return to the correct alignment positions.
8. Reassemble Components: Reinstall the timing belt cover and any other removed components in reverse order of disassembly. Torque all fasteners to specification.
9. Final Check: Reconnect the battery and start the engine. Listen for unusual noises and verify smooth operation at idle and under load.
10. Test Run: Conduct a brief test run on the water to ensure proper engine performance and timing synchronization. Monitor for any abnormal sounds or vibrations.

Troubleshooting & FAQ

Q: How do I confirm this timing belt fits my specific engine?
A: Cross-reference your engine's model and year with the compatibility table above. Also verify your current belt's OEM part number (66M-46241-00, 57-835392Q, 18-15147, or 3H8-10061-0) matches one listed in the part number table.

Q: What are the signs that my timing belt needs replacement?
A: Common symptoms include visible cracks or fraying on the belt, engine misfiring or rough idle, difficulty starting, unusual ticking or slapping noises from the engine, or oil leaks around the timing cover. Replace immediately if any damage is visible.

Q: How often should I replace the timing belt on my outboard?
A: Most manufacturers recommend timing belt replacement every 3-5 years or 300-500 operating hours, whichever comes first. Always consult your engine's service manual for specific maintenance intervals, and inspect the belt annually for wear.

Q: Can I install this timing belt myself or do I need a professional?
A: While experienced mechanics can perform this replacement, incorrect timing belt installation can cause severe engine damage including bent valves or piston contact. Professional installation is strongly recommended unless you have the proper tools, service manual, and mechanical expertise.

Q: What's the difference between this aftermarket belt and the OEM version?
A: This aftermarket timing belt is manufactured to OEM specifications using comparable-grade materials in an ISO9002-certified facility. It provides equivalent performance and durability to OEM belts while offering better value, making it a reliable replacement option.

Q: Is this an OEM part or an aftermarket replacement?
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.