Mercury Outboard Lower Unit Replacement – Fits 3L – 1.62 & 1.75 Ratios - Counter Rotation - Aftermarket

Mercury Outboard Lower Unit Replacement – Fits 3L – 1.62 & 1.75 Ratios – Counter Rotation – Aftermarket

The SE218 counter rotation lower unit is engineered to replace most Mercury 3.0L outboards (serial number 1B504989 and below). Perfect for marine enthusiasts demanding long-lasting reliability, this robust, aftermarket assembly is available with 25" or 30" 13-spline one-piece drive shafts and supports both 1.62:1 and 1.75:1 gear ratios for optimal performance in counter-rotation setups.

Key Features

• Designed for Mercury 3.0L V6 outboards (SN 1B504989 and below)

• Supports counter rotation for twin-engine configurations

• Available in 1.62:1 and 1.75:1 gear ratios

• Shaft options: 25" or 30" (13 spline) one-piece drive shaft

• Stub shaft version available for engines with 8-spline drive

• Not compatible with Torque Master, Torque Master 2, or Sport Master

Specifications Table

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Compatibility Notes

• For 8-spline setups, purchase the stub shaft unit and an OE upper driveshaft.

• If unit serial is lower than OG438000, use your old water coupling or purchase SEI #96-116-12K.

• 13-spline two-piece shaft users: upgrade to the matching one-piece shaft as listed.

For expert fitment guidance, please call 888 868 7880 with your engine serial number.

Browse more lower unit options:

All Mercury Lower Units

Official resources: Mercury Marine