WSM Piston Rings Mercury / Mariner 105-200 HP 78-05 .015 Over OEM# 39-78918A12 39-78918A4 S18-3922 – WSM 200-30-045

Piston Rings Mercury / Mariner 105 - 200 Hp 78-05 .015 Over OEM# 39-78918A12 OEM# 39-78918A12 39-78918A4 S18-3922

This WSM piston rings is a quality aftermarket replacement part designed for Mercury Mariner 5-0 Hp .5 Over.

It replaces selected OEM reference numbers including 39-78918A12 and is suitable for service, repair and rebuild work.

Key Features

• Quality replacement component for engine rebuild and repair
• Manufactured for dependable fitment and consistent performance
• Suitable for professional workshop or enthusiast use
• Compatible with 1 listed fitment
• Replaces selected OEM reference numbers listed below

Product Details

• Brand: WSM
• WSM Part Number: 200-30-045
• Product: Piston Rings
• OEM Reference: 39-78918A12
• Application: Mercury Mariner 5-0 Hp .5 Over

Product Fitment

This part is suitable for the following models:

• Mercury Mariner 5-0 Hp .5 Over

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.

About the Mercury 135-200 HP Outboard Engines

Mercury and Mariner 135-200 HP outboard engines are widely used across recreational and performance boating applications. These engines have long-standing aftermarket support, making quality replacement gaskets, ignition, fuel and powerhead parts important for service and rebuild work.

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• Bearing Needles With Washers Mercury / Mariner 70 - 125 / 200 - 300 Hp OEM# 29-88258 – 010-120-34
• Bearing Needles Mercury / Mariner 105 - 240 Hp Big Pin OEM# 29-822553 – 010-137-34

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