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Thermostat Gasket – Fits Yamaha 20-250HP Outboards (Replaces 61A-12414-A0-00)

Regular price $16.95
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Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This high-quality Thermostat Gasket – Fits Yamaha 20-250HP Outboards (Replaces 61A-12414-A0-00) ensures a reliable seal for the thermostat housing on a wide range of Yamaha engines. It is designed for various 2-stroke and 4-stroke outboard motors from 20 to 250 HP, covering model years from 1992 to 2005.

This part serves as a direct replacement for Yamaha OEM part numbers 61A-12414-A0-00, 6J8-12414-A0-00, and 6H4-12414-00-00.

  • Engineered for a direct-fit installation.
  • Creates a durable, leak-proof seal between the thermostat and its housing.
  • Made from professional-grade composite gasket material.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand Part Number Superseded By
Yamaha 6H4-12414-00-00 6J8-12414-A0-00
Yamaha 6J8-12414-A0-00 61A-12414-A0-00
Yamaha 61A-12414-A0-00

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This gasket is designed for the following Yamaha outboard models:

Model Rated HP Stroke Years OEM Part No. Notes
20MLHU 20 2-Stroke 1996 61A-12414-A0-00
20MLHV 20 2-Stroke 1997 61A-12414-A0-00
20MSHU 20 2-Stroke 1996 61A-12414-A0-00
20MSHV 20 2-Stroke 1997 61A-12414-A0-00
25ELHU/V/W/X 25 2-Stroke 1996–1999 61A-12414-A0-00
25ELRU/V/W/X 25 2-Stroke 1996–1999 61A-12414-A0-00
25ESHU/V/W/X 25 2-Stroke 1996–1999 61A-12414-A0-00
25MLHU/V/W/X series 25 2-Stroke 1996–1999 61A-12414-A0-00 Includes 25MLHU2, 25MLHV2, etc.
25MSHU/V/W/X series 25 2-Stroke 1996–1999 61A-12414-A0-00 Includes 25MSHU2, 25MSHV2, etc.
30ELHT/U/V/W 30 2-Stroke 1995–1998 61A-12414-A0-00
30ELRT/U/V/W 30 2-Stroke 1995–1998 61A-12414-A0-00
30ESRT/U/V/W 30 2-Stroke 1995–1998 61A-12414-A0-00
30MLHT/U/V/W 30 2-Stroke 1995–1998 61A-12414-A0-00
30MSHT/U/V/W 30 2-Stroke 1995–1998 61A-12414-A0-00
40EJRV/W/X/Y/Z 40 4-Stroke 1997–2001 61A-12414-A0-00
40ELRV/W 40 2-Stroke 1997–1998 61A-12414-A0-00
40ESRV/W/X 40 2-Stroke 1997–1999 61A-12414-A0-00
40MJHV/W/X/Y/Z 40 2-Stroke 1997–2001 61A-12414-A0-00
40MLHV/W/X/Y/Z 40 2-Stroke 1997–2001 61A-12414-A0-00
40MSHV/W/X 40 2-Stroke 1997–1999 61A-12414-A0-00
40TLHV 40 2-Stroke 1997 61A-12414-A0-00
40TLRV/W/X/Y/Z/A/B 40 2-Stroke 1997–2003 61A-12414-A0-00
C40TLRV/W/X/Y/Z/A/B 40 2-Stroke 1997–2003 61A-12414-A0-00 Commercial model
50EJRV/W/X/Y/Z 50 4-Stroke 1997–2001 61A-12414-A0-00
50ELRV/W 50 2-Stroke 1997–1998 61A-12414-A0-00
50TLHV 50 2-Stroke 1997 61A-12414-A0-00
50TLRV/Z/A/B 50 2-Stroke 1997–2003 61A-12414-A0-00 Some model years missing
C50TLRW/X/Y/Z 50 2-Stroke 1998–2001 61A-12414-A0-00 Commercial model
225TURT 225 2-Stroke 1995 61A-12414-A0-00
225TXRS/T 225 2-Stroke 1994–1995 61A-12414-A0-00
250TURQ/R/S/T 250 2-Stroke 1992–1995 61A-12414-A0-00
250TXRQ/R/S/T 250 2-Stroke 1992–1995 61A-12414-A0-00
L225TURT/U/V/W 225 2-Stroke 1995–1998 61A-12414-A0-00 Long shaft
L225TXRS/T/U/V/W/X 225 2-Stroke 1994–1999 61A-12414-A0-00 Long shaft
L250TURQ/R/S/T/U/V/W/X 250 2-Stroke 1992–1999 61A-12414-A0-00 Long shaft
L250TXRQ/R/S/T/U/V/W/X 250 2-Stroke 1992–1999 61A-12414-A0-00 Long shaft
LX225TXRY/Z/A/B 225 2-Stroke 2000–2003 61A-12414-A0-00
LX250TURY/Z/A 250 2-Stroke 2000–2002 61A-12414-A0-00
LX250TXRY/Z/A/B 250 2-Stroke 2000–2003 61A-12414-A0-00
P40TLHW 40 2-Stroke 1998 61A-12414-A0-00
P40TLRW 40 2-Stroke 1998 61A-12414-A0-00
S225TURU/V/W/X 225 2-Stroke 1996–1999 61A-12414-A0-00
S225TXRU/V/W/X 225 2-Stroke 1996–1999 61A-12414-A0-00
S250TURU/V/W/X 250 2-Stroke 1996–1999 61A-12414-A0-00
S250TXRU/V/W/X 250 2-Stroke 1996–1999 61A-12414-A0-00
SX225TURY/Z/A/B 225 2-Stroke 2000–2003 61A-12414-A0-00
SX225TXRY/Z/A/B 225 2-Stroke 2000–2003 61A-12414-A0-00
SX250TURY/Z/A/B 250 2-Stroke 2000–2003 61A-12414-A0-00
SX250TXRY/Z/A/B 250 2-Stroke 2000–2003 61A-12414-A0-00
V200TLRW/X 200 V6 1998–1999 61A-12414-A0-00
V225TLRW/X 225 V6 1998–1999 61A-12414-A0-00
VX200TLRY/Z/A/B/C/D 200 V6 2000–2005 61A-12414-A0-00
VX225TLRY/Z/A/B/C 225 V6 2000–2004 61A-12414-A0-00
VX250TLRA/B/C 250 V6 2002–2004 61A-12414-A0-00

Technical Specs

Product Type
Thermostat Cover Gasket
Installation
Direct fit
Material
Gasket material (paper/composite)
Compatible Engines
Yamaha 2-stroke and 4-stroke outboards
Horsepower Range
20–250 HP
Model Years
1992–2005
Application
Seals between thermostat and housing
Dimensions
5.13 in x 4.0 in x 1.03 in
Weight
0.06 kg (0.13 lb)

What’s in the Box

  • 1 x Thermostat Gasket (Replaces 61A-12414-A0-00)

Installation Notes

  1. Ensure the engine is off and cool. Disconnect the negative battery terminal for safety.
  2. Locate the thermostat housing on the engine block and place a drain pan underneath.
  3. Carefully remove the bolts securing the thermostat cover. Note their length and position if they differ.
  4. Gently tap the cover to break the seal, then lift it away. Be prepared for some residual coolant to spill.
  5. Remove the old gasket. Scrape away any remaining gasket material from both the housing and cover surfaces. Ensure both mating surfaces are perfectly clean and smooth.
  6. Place the new gasket into position, ensuring all bolt holes align correctly.
  7. Reinstall the thermostat cover and tighten the bolts in a crisscross pattern to the manufacturer's specified torque. Do not overtighten.
  8. Reconnect the battery terminal and properly refill the engine's cooling system. Start the engine and carefully check for any leaks around the housing.

Troubleshooting & FAQ

How do I confirm this gasket fits my specific Yamaha model?

This gasket fits a broad range of Yamaha outboards from 20-250 HP manufactured between 1992 and 2005. The best way to ensure compatibility is to check the "Engine & Model Compatibility" table on this page. Match your engine's model number and year against the list provided.

What are the signs of a failing thermostat gasket?

Common signs of a bad thermostat gasket include visible coolant leaks around the thermostat housing, engine overheating alerts, or a consistently high temperature gauge reading. You may also notice steam coming from the engine cowling or a sweet smell of antifreeze.

Do I need to use sealant or adhesive with this gasket?

In most cases, this gasket is designed to be installed dry without any additional sealants. Applying sealant can sometimes cause the gasket to slip out of place during installation. Always follow the service manual for your specific engine model.

What’s the difference between an OEM part and this aftermarket one?

This listing is for a high-quality aftermarket replacement part, not an OEM (Original Equipment Manufacturer) component. It is engineered to meet or exceed OEM-level specifications using comparable materials and manufacturing processes. Our parts are produced in an ISO 9002 certified facility and undergo batch inspections to ensure consistent quality and fitment.

How fast is shipping and what does it cost?

We ship worldwide quickly—typical transit time is 5–15 days for most regions. Standard shipping is free on all orders. Expedited shipping options and associated costs, if available for your location, will be displayed at checkout.

What is the warranty and return policy?

This product is covered by a 1-year warranty against manufacturing defects under conditions of normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original packaging. Please see our full policy page or reach out for return instructions.

Safety & Important Info

  • Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
  • This is an aftermarket replacement, not an OEM component.
  • Professional installation is recommended for safety and performance.

About Sea Sierra

  • Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
  • Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
  • Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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