# 6E5-12411-30 Yamaha Thermostat | Genuine OEM Yamaha Outboard Part

🔧 Product Description

  

Genuine Yamaha 50°C Two-Stroke Outboard Thermostat - Part Number: 6E5-12411-30

  

A genuine Yamaha thermostat calibrated to approximately 50°C / 122°F for selected Yamaha two-stroke outboards.

  

The thermostat regulates cooling-water circulation through the cylinder block and cylinder head. It restricts flow during warm-up before opening at its calibrated temperature to help maintain stable combustion, idle quality and operating temperature.

  

⚙️ Key Features

  

• Genuine Yamaha OEM marine thermostat

• Correct current Yamaha part number 6E5-12411-30

• Approximately 50°C / 122°F opening temperature

• Supplied with the thermostat sealing grommet where packaged by Yamaha

• Cross-references with Sierra and Mallory marine thermostats

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 6E5-12411-30 → Supersedes 6E5-12411-20

• 6E5-12411-20 → Supersedes 6E5-12411-10

• 6E5-12411-10 → Replaces 688-12411-11

• 688-12411-11 → Supersedes 688-12411-10

• 688-12411-10 → Supersedes 688-12411-01

• 688-12411-01 → Supersedes 688-12411-00

  

OEM / Related Numbers:

  

• 6E5-12411-30

• 6E5-12411-30-00

• 6E5-12411-20

• 6E5-12411-10

• 688-12411-11

• 688-12411-10

• 688-12411-01

• 688-12411-00

• 6H3-12411-11 related thermostat reference

  

Aftermarket / Verified Equivalents:

  

• Sierra: 18-3540

• Sierra: 18-3623

• Mallory: 9-43035

• Offshore Marine Parts: 75107500

• Aftermarket 50°C thermostat: 6E5-12411-30 replacement

  

🚤 Compatibility

  

Commonly used on:

  

• Yamaha two-stroke cylinder-head cooling systems

• Conventional, Saltwater Series, VMAX and HPDI outboard engines

  

Typically suits:

  

• Engine models:

• Yamaha 9.9F two-stroke

• Yamaha 15F two-stroke

• Yamaha 25N two-stroke

• Yamaha 30D two-stroke

• Yamaha 40V and C40 two-stroke

• Yamaha 50HP two-stroke applications using the 6E5 thermostat family

• Yamaha 60HP and 70HP two-stroke applications where specified

• Yamaha 75C two-stroke

• Yamaha 90A / 90TLR two-stroke

• Yamaha 100A two-stroke

• Yamaha 115C two-stroke

• Yamaha 130B two-stroke

• Yamaha 140C two-stroke

• Yamaha 150F, V150, VX150, DX150 and LZ150

• Yamaha 175D, VZ175 and Z175

• Yamaha 200F, 200G, LZ200, SX200, VX200, VZ200 and Z200

• Yamaha 225D, 225G, LX225, SX225 and VX225

• Yamaha 250A, 250B, LX250, SX250 and VX250

• Yamaha HPDI Z150P / Z150Q, Z175G and Z200N / Z200P

  

• HP Range: Approximately 9.9HP - 250HP

• Engine Type: Yamaha carburetted, EFI and HPDI two-stroke outboard

• Year Range: Approximately 1984-2006, dependent on engine model and production code

  

🔌 Function

  

The thermostat controls cooling-water flow so the powerhead reaches operating temperature promptly and remains within its intended temperature range.

  

Common signs of failure:

  

• Engine overheats because the thermostat remains closed

• Engine runs excessively cold because the thermostat remains open

• Unstable cylinder-head temperature

• Poor idle or excessive smoke during warm-up

• Salt, corrosion or debris prevents the valve moving freely

  

📦 Condition

  

• Genuine Yamaha part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 60.0 AUD
- **Vendor:** Yamaha
- **Tags:** Yamaha Marine Parts | Outboard Engine Parts & Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 60.00 AUD | In stock |

## Images

- 6E5-12411-30 Yamaha Thermostat | Genuine OEM Yamaha Outboard Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/6e5-12411-30-00-thermostat)
> Updated: 2026-07-11