Mercury Outboard Lower Unit Replacement – Fits 3.0L V6 / 2.6L I6 / 1.7L I4 (13 & 20 Splines) – 1.75 / 1.85 / 2.08 Ratios

Mercury Outboard Lower Unit Replacement – Fits 3.0L V6 / 2.6L I6 / 1.7L I4 (13 & 20 Splines) – 1.75 / 1.85 / 2.08 Ratios – Aftermarket

The SE221 gearcases are designed to fit a variety of Mercury outboard engines, including 3.0 Liter V6 two-stroke, 2.6 Liter inline 6 four-stroke, and 1.7 Liter inline 4 four-stroke Verado models. These premium aftermarket lower units deliver reliability and a precise fit for specified models and serial ranges.

Engine Fitment Details

• 3.0 Liter V6 Two Stroke (13 spline) Compatible with SEI 221-A20, 221-A25, and 221-A30 units Replaces models from circa 2006 and later starting at serial #1B504989 Note: Not compatible with Torque Master, Torque Master 2, or Sport Master (“Fat Shaft” 19 spline)

• 2.6 Liter Inline 6 Four Stroke (20 spline) Fits Verado 200–300 HP models with SE 221-A20F, 221-A25F, 221-A30F, 221-B20F, 221-B25F, and 221-B30F For use with 4.8 Torpedo units; no replacement for 5.44 Torpedo

• 1.7 Liter Inline 4 Four Stroke (20 spline) Designed for smaller Verado models, 135–200 HP, featuring superchargers Available in standard or counter rotation versions Not compatible with non-Verado inline 4 cylinder four strokes lacking superchargers

Specifications

Note: Installation kit and anode kit are not included. Verify your exact model and serial number before ordering.

For fitment help or questions, contact us with your serial number.

Browse all Mercury Lower Units: Mercury Lower Units

Official Mercury Marine specs: Mercury Marine