Thermostat Kit – Fits Honda Outboard 4-Stroke BF5 to BF100 (Replaces 19300-881-761)

Thermostat Kit – Fits Honda Outboard 4-Stroke BF5 to BF100 (Replaces 19300-881-761)

This thermostat kit is engineered for a wide range of Honda 4-stroke marine outboard engines from 5 to 100 HP, covering models from 1997 to 2007 and newer. It ensures your engine maintains the correct operating temperature for optimal performance and longevity.

This kit serves as a direct replacement for Honda part number 19300-881-761, Sierra 18-3627, and OVERSEE 19300-881-761, providing a reliable aftermarket solution.

• Engineered to maintain a consistent operating temperature of 50–52°C (122–125.6°F).
• Designed for direct replacement, ensuring a straightforward installation process.
• Complete kit includes a thermostat, gasket, and two rubber seal rings for a comprehensive service.

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.

Technical Specifications

Package Contents

• 1 x Thermostat (19300-881-761)
• 2 x Rubber Seal Rings (19302-921-003)
• 1 x Thermostat Gasket (19351-ZV4-610)

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is cool.
2. Drain Coolant: Drain the engine's cooling system partially to a level below the thermostat housing.
3. Locate Housing: Find the thermostat housing, typically located on the cylinder head.
4. Remove Bolts: Carefully unbolt and remove the thermostat housing cover.
5. Extract Old Parts: Remove the old thermostat, gasket, and any seals. Note their orientation.
6. Clean Surfaces: Thoroughly clean the mating surfaces of the housing and cylinder head to ensure a proper seal.
7. Install New Parts: Place the new thermostat, gasket, and seals into the housing in the correct order and orientation.
8. Reassemble: Re-install the housing cover and tighten the bolts to the manufacturer's recommended torque specifications.
9. Refill and Check: Refill the cooling system. Reconnect the battery, start the engine, and carefully check for any leaks around the housing as the engine warms up.

Troubleshooting & FAQ

Q: How do I confirm this thermostat kit will fit my specific Honda engine?
A: The best way is to check the Compatible Engine Models table on this page. Cross-reference your engine's model, horsepower, and year. You can also verify by matching your existing part number with those listed in the Part Number Cross-Reference table.

Q: What are the common signs of a failing outboard thermostat?
A: Symptoms include engine overheating, especially at idle or low speeds, or the engine taking an unusually long time to reach its normal operating temperature. You might also notice erratic readings on the temperature gauge.

Q: Why is the 50-52°C operating temperature important?
A: This specific temperature range is vital for Honda outboards to ensure efficient combustion, prevent carbon buildup, and reduce engine wear. Using a thermostat with the wrong temperature rating can lead to poor performance and long-term engine damage.

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.