Thermostat Kit – Fits Honda Outboard BF5-BF100 (Replaces 19300-881-761, 18-3627)
Thermostat Kit – Fits Honda Outboard BF5-BF100 (Replaces 19300-881-761, 18-3627) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Thermostat Kit – Fits Honda Outboard BF5-BF100 (Replaces 19300-881-...
Thermostat Kit – Fits Honda Outboard BF5-BF100 (Replaces 19300-881-761, 18-3627) is backordered and will ship as soon as it is back in stock.
Product Details
This Thermostat Kit – Fits Honda Outboard 4-Stroke BF5 to BF100 (Replaces 19300-881-761) is designed for a broad range of Honda 4-stroke marine outboards from 5 to 100 HP, covering model years 1997 through 2007 and newer. It ensures your engine maintains the correct operating temperature for optimal performance and longevity.
It serves as a direct replacement for Honda part 19300-881-761, Sierra 18-3627, and OVERSEE 19300-881-761, providing a reliable aftermarket alternative.
- Engineered for direct-fit installation on the cylinder head.
- Maintains a precise operating temperature of 50–52°C (122–125.6°F).
- The kit includes one thermostat, one gasket, and two rubber seal rings for a complete installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Honda | 19300-881-761 |
| Sierra | 18-3627 |
| OVERSEE | 19300-881-761 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This thermostat kit is confirmed to fit the following Honda outboard models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Honda | BF50F-LA, BF50F-SA | 50 | 4-Stroke | 1997–2007+ | 19300-881-761 | Cylinder head application |
| Honda | BF5A Series (LA/SA variants) | 5 | 4-Stroke | 1997–2007+ | 19300-881-761 | Includes BF5A1, BF5A2, BF5A4, BF5A5, BF5A6 |
| Honda | BF5AK0, BF5AK2, BF5AK3 (LA/SA) | 5 | 4-Stroke | 2007+ | 19300-881-761 | |
| Honda | BF5AH, BF5AX, BF5AM, BF5AY | 5 | 4-Stroke | 1997–2000 | 19300-881-761 | Pre-2001 models |
| Honda | BF5AW (SA) | 5 | 4-Stroke | 1998 | 19300-881-761 | 1998 model year only |
| Honda | BF6B, BF6BX | 6 | 4-Stroke | 1997–2007+ | 19300-881-761 | |
| Honda | BF6AH (LHNA/SHNA) | 6 | 4-Stroke | 2007+ | 19300-881-761 | |
| Honda | BF75F | 7.5 | 4-Stroke | 1997–2007+ | 19300-881-761 | |
| Honda | BF8 Series | 8 | 4-Stroke | 1997–2007+ | 19300-881-761 | Includes BF8AH, BF8AK, BF8AM, BF8AX, BF8BX, BF8B |
| Honda | BF9.9 Series | 9.9 | 4-Stroke | 1997–2007+ | 19300-881-761 | Includes BF9.9AH, BF9.9AK, BF9.9AM, BF9.9B, BF9.9AX, BF9.9BX |
| Honda | BF100F | 10 | 4-Stroke | 1997–2007+ | 19300-881-761 | |
| Honda | BF15 Series | 15 | 4-Stroke | 1997–2007+ | 19300-881-761 | Includes BF15A1, BF15A2, BF15AH, BF15AK, BF15AM, BF15AX, BF15B, BF15B2, BF15BX |
| Honda | BF5DH (LHNA/SHNA) | 5 | 4-Stroke | 2007+ | 19300-881-761 |
Technical Specs
- Product Type
- Marine Outboard Engine Thermostat Kit
- Installation
- Direct replacement
- Operating Temperature
- 50–52°C (122–125.6°F)
- Housing Material
- High-grade corrosion-resistant alloy
- Connection
- Direct fit to cylinder head
- Warranty
- Varies by manufacturer (typically 1 year)
What’s in the Box
- 1 x Thermostat (19300-881-761)
- 2 x Rubber Seal Rings (19302-921-003)
- 1 x Thermostat Gasket (19351-ZV4-610)
Installation Notes
- Ensure the engine is off and cool. Disconnect the negative battery terminal.
- Place a drain pan under the engine and carefully drain the cooling system.
- Locate the thermostat housing on the cylinder head. Remove the bolts securing the housing cover.
- Gently tap the housing if it's stuck, then lift it away to expose the thermostat.
- Note the orientation of the old thermostat before removing it, along with the old gasket and seals.
- Thoroughly clean the mating surfaces of the housing and cover, removing all old gasket material.
- Install the new rubber seals and gasket, followed by the new thermostat in the correct orientation.
- Re-secure the housing cover, tightening bolts to the manufacturer's specified torque.
- Refill the cooling system with the recommended coolant. Reconnect the battery.
- Start the engine, let it reach operating temperature, and carefully check for any leaks around the housing.
Troubleshooting & FAQ
How do I know if this thermostat fits my specific Honda engine?
The best way to confirm fitment is to check your engine's model and year against the compatibility table provided on this page. You can also match the OEM part number 19300-881-761 with the one listed in your engine's service manual.
What are the common signs of a failing thermostat?
A faulty thermostat can cause engine overheating (if stuck closed) or prevent the engine from reaching its proper operating temperature (if stuck open). You might notice alarm warnings, poor performance, or inconsistent temperature gauge readings.
Is 50-52°C the correct temperature range for my engine?
Yes, this thermostat is designed to open at 50-52°C (122-125.6°F), which is the specified range for the listed Honda outboard models to ensure efficient combustion and prevent engine wear.
Can I install this kit myself?
While installation is straightforward for those with mechanical experience, we recommend professional installation. The process involves draining coolant and requires careful cleaning and torqueing of components to prevent leaks and ensure safety.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility. All parts are batch-inspected for quality and consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout if they are available for your location.
Warranty & returns
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not install the part.
- This is an aftermarket replacement component, not an original equipment manufacturer (OEM) product.
- Professional installation is highly recommended for safety, performance, and to prevent potential damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world saltwater and freshwater conditions.
- Fast Global Fulfillment — With free standard delivery to most regions, you can expect your parts in 5–15 days. We get you back on the water, faster.
- Manufacturer-Direct Value — By working directly with manufacturers, we offer fair pricing without compromising on materials or quality control.
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