Heating and Cooling› Thermostats, Housings and Fillers

SIERRAMARINE

THERMOSTAT

$31.46

SKU: S08C 18-3543

In Stock
In Stock
Ships by Jun 18
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Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Easy — 1–2 hours

Description

The Sierra 18-3543 is a Johnson/Evinrude thermostat with a temperature rating of 143 degrees Fahrenheit. It is designed to meet OEM specifications and is interchangeable with several Johnson/Evinrude part numbers, including 393659, 434841, 378065, 508626, 5005440, and 437414. This thermostat is also interchangeable with EMP part number 75-00403.

The thermostat is suitable for use on engine models ranging from 40-250 HP E-Tech, 6-55 HP, Cross V4 & V6, and specific 4-stroke models including 9.9 HP (1994-2001) and 15 HP (1994-2001).

Fitment

Fitment Guaranteed

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on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandSIERRAMARINE
Part NumberS08C 18-3543

Buy with Confidence

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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