6DR-14301-00 Thermostat for Yamaha F9.9J FT9.9L T9.9MHB | JLM Marine

Thermostat for Yamaha F9.9J FT9.9L T9.9MHB – Fits Yamaha 9.9HP Outboards

This aftermarket thermostat is engineered to fit select Yamaha 9.9HP outboard models, including the F9.9J, FT9.9L, and T9.9MHB. It ensures proper engine temperature regulation for consistent performance and longevity.

This part directly replaces OEM part number 6DR-14301-00, providing a reliable and cost-effective solution for maintaining your outboard's cooling system.

• Direct replacement for Yamaha part number 6DR-14301-00
• Designed for Yamaha 9.9HP four-stroke outboards
• Ensures optimal engine operating temperature

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 x Thermostat (Part No. 6DR-14301-00)

Installation Guide

1. Ensure the engine is completely cool before starting work. Disconnect the battery to prevent accidental starting.
2. Drain the cooling system and locate the thermostat housing on your engine. Consult your service manual for the exact location.
3. Remove the bolts securing the thermostat housing cover. Carefully lift the cover and remove the old thermostat.
4. Clean the mating surfaces of the housing and cover thoroughly, removing all old gasket material and debris.
5. Install the new thermostat in the correct orientation (spring side typically faces inward toward the engine). Ensure proper seating in the housing recess.
6. Replace the housing gasket or O-ring with a new one if available. Apply a thin coat of marine-grade sealant if recommended by the manufacturer.
7. Reinstall the thermostat housing cover and torque bolts to manufacturer specifications in a criss-cross pattern.
8. Refill the cooling system with the appropriate coolant or allow water circulation to resume. Check for leaks around the housing.
9. Reconnect the battery and start the engine. Monitor operating temperature to confirm proper thermostat function.
10. Allow the engine to reach normal operating temperature and verify no coolant leaks. Top off coolant if necessary.

Troubleshooting & FAQ

Q: How do I confirm this thermostat fits my Yamaha outboard?
A: Verify your engine model against the compatibility table above (F9.9J, FT9.9L, T9.9MHB). Cross-check your current thermostat's part number with 6DR-14301-00 or use the Yamaha parts diagrams linked in the Compatible Engine Models section.

Q: What are the signs that my thermostat needs replacement?
A: Common symptoms include engine overheating, running too cool (long warm-up times), inconsistent temperature readings, or coolant leaks near the thermostat housing. If your engine fails to reach normal operating temperature, the thermostat may be stuck open.

Q: How often should I replace the thermostat on my Yamaha outboard?
A: Yamaha recommends inspecting the thermostat during routine maintenance intervals (typically every 100 hours or annually). Replace it if you notice corrosion, failure to open/close properly, or as part of cooling system service every 2–3 years depending on usage and water conditions.

Q: Can I install this thermostat myself or do I need a professional?
A: If you have basic mechanical skills and tools, thermostat replacement is straightforward. However, proper torque specifications and coolant handling are critical; professional installation is recommended if you're unfamiliar with outboard cooling systems.

Q: Is this an OEM Yamaha 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.