Aftermarket Thermostat 50°C (122°F) for Yamaha F115, LF115 & HPDI 200–300 HP – Replaces 60V-12411-00

Product Details

This aftermarket 50°C (122°F) thermostat is designed for selected Yamaha outboard applications, including F115 and LF115 four-stroke models and HPDI 200–300 HP two-stroke models. It helps regulate engine operating temperature and is supplied as one thermostat for replacement service.

The thermostat is listed as a replacement for Yamaha part numbers 60V-12411-00 and 68V-12411-00. It is also identified with aftermarket reference Sierra 18-3525 and Mercury Marine references 881429 and 8M6010295.

• Aftermarket replacement thermostat for selected Yamaha outboards.
• Opening temperature: 50°C (122°F).
• Single thermostat supplied; gasket or O-ring is not included unless specifically stated for your order.
• Confirm the engine model and year before ordering.

Part Number Matrix

Use the references below to compare the thermostat with the part being replaced. These numbers should be verified against your engine documentation and original component.

Engine & Model Compatibility

The company fitment information identifies the following Yamaha applications. Model codes, production years, and serial ranges can vary, so match the complete engine identification before purchase.

Technical Specifications

Product Type

Outboard motor thermostat

Application

Selected Yamaha outboard engines

Opening Temperature

50°C (122°F)

Product Style

Aftermarket replacement component

Quantity

1 thermostat

What's in the Box

• 1 x 50°C (122°F) replacement thermostat

Not included: gasket, O-ring, sealant, or other installation hardware unless separately stated in the order.

Installation Notes

1. Turn the engine off and allow it to cool completely before beginning work.
2. Disconnect the battery according to the engine manufacturer's safety procedure.
3. Locate the thermostat housing and place a suitable container beneath the service area to collect water or residual fluid.
4. Remove the housing cover carefully and note the original thermostat orientation.
5. Remove the old thermostat and gasket or O-ring. Replace the gasket or O-ring with a new, correct part if required.
6. Clean the mating surfaces without damaging the housing or cylinder-head sealing area.
7. Install the new thermostat in the same orientation as the original component.
8. Reinstall the housing cover and tighten the fasteners evenly to the manufacturer's specified torque.
9. Restore any removed connections, run the engine according to the service manual, and check for leaks and proper water flow.
10. Stop the engine immediately if it overheats, leaks, or shows abnormal temperature behavior.

Troubleshooting & FAQ

Safety & Important Information

• Verify the complete engine model, year, serial information where applicable, and original thermostat reference before ordering.
• Do not rely on horsepower alone to determine compatibility.
• Installation should follow the applicable Yamaha service information and torque specifications.
• This is an aftermarket replacement component and is not manufactured or branded by Yamaha.
• Professional marine-service installation is recommended when the cooling system or thermostat housing cannot be safely serviced by the owner.

About Sea Sierra

• Marine Replacement Parts — Practical replacement components for routine outboard maintenance and repair.
• Fitment-Focused Listings — Product references and engine applications are provided to help customers compare before ordering.
• Service-Ready Information — Clear specifications and installation notes support proper part selection and maintenance.