Gasket Thermostat - Mercury / Mariner 200 / 225 HP (1998) OEM# 27-850318 | WSM 516-39

Gasket Thermostat Mercury / Mariner 200 / 225 Hp OEM# 27-850318

This WSM gasket thermostat is a quality aftermarket replacement part designed for Mariner 6 Cyl 3.6265 Bore 3L Optimax 200 and 2 other compatible models.

It replaces selected OEM reference numbers including 27-850318, S18-3675 and is suitable for service, repair and rebuild work.

Key Features

• Quality replacement gasket designed for dependable sealing performance
• Ideal for service, repair and engine rebuild work
• Manufactured for fit, durability and reliable installation
• Compatible with 3 listed fitments
• Replaces selected OEM reference numbers listed below

Product Details

• Brand: WSM
• WSM Part Number: 516-39
• Product: Gasket Thermostat
• OEM Reference: 27-850318, S18-3675
• Application: Mariner 6 Cyl 3.6265 Bore 3L Optimax 200 and 2 other compatible models

Product Fitment

This part is suitable for the following models:

• Mariner 6 Cyl 3.6265 Bore 3L Optimax 200 – All Years
• Mercury 6 Cyl 3.6265 Bore 3L Optimax 225 – 1998
• Mercury – 1998

Why Buy WSM

WSM is a trusted manufacturer of aftermarket marine and powersports parts, known for dependable quality, strong fitment coverage and workshop-ready replacement components.

You May Also Need

Browse related parts for compatible models:

• Powerhead Rebuild Kit Mercury / Mariner 200 - 250 Hp 3L Optimax .020 Over – 100-47-12
• O-Ring Cylinder Head Mercury / Mariner 200 - 300 Hp OEM# 25-818573 – 505-51
• Fuel Pump Mercury / Mariner 135 - 225 Hp DFI OEM# 855427A1 – 600-113
• Fuel Pump Mercury / Mariner 135 - 225 Hp DFI OEM# 855427A1 – 600-113-W

Please use the fitment guide, OEM references and images to confirm this is the correct part before ordering.