4HP / 5HP Mariner Outboard Base Gasket JAPAN Models Only (2-Stroke)

Replaces 27-91780 / 91780M Yamaha-Built Mariner UK Stock

Product Description

Base gasket for Mariner 4HP and 5HP 2-stroke outboards, Japan-built models made by Yamaha. These engines have serial numbers starting with 6E0 or 6E3 and share many parts with Yamahas 4A and 5C series.

This gasket fits between the powerhead and the midsection to properly seal the lower end of the engine. High-quality aftermarket part with OEM-style fit.

Fitment

• Mariner 4HP / 5HP

• 2-Stroke

• Japan models only

• Serial number starts with 6E0 or 6E3

• Based on Yamaha 4A / 5C design

Will NOT fit Mariner engines made by Mercury USA or Belgium.

Replaces Mariner Part Numbers

• 27-91780

• 27-91780M

• 91780

• 91780M

Why Buy from SSI MARINE?

• All parts are stocked in the UK

• Selected by marine technicians for fit and quality

• Same-day dispatch before 1 PM (MonFri)

• Collection available from our Leigh (Manchester) workshop

If you’re unsure about compatibility, contact us with your serial number and well confirm the fit.

Shipping & Collection

• Tracked 24-hour UK delivery

• Same-day dispatch before 1 PM

• In-person collection available Monday to Friday