Replacement Yamaha Lower Unit | 2.0 | 20" | 2 Stroke | 90-404-A20

SE404 Replacement Lower Unit for Yamaha® 75–100 HP

OEM-fit performance without the OEM price. The SE404 is engineered as a reliable, direct-fit alternative for select Yamaha 2-Stroke and 4-Stroke outboards. Built to factory specifications for smooth shifting, long service life, and dependable on-water performance, each unit arrives fully assembled and ready to install for a hassle-free replacement.

Highlights

• Direct-fit coverage for select Yamaha 2-Stroke & 4-Stroke 75–100 HP models (standard rotation)
• Excludes newer models — not compatible with 2016+ 4-Stroke engines whose model codes end in “B”
• Complete assembly — water pump and all internal components pre-installed
• OEM-quality construction — precision-machined gears, shafts, and bearings for smooth operation
• Durable finish — painted black; can be refinished to match your Yamaha
• Cost-effective — quality replacement at a fraction of OEM pricing

Application

Direct replacement for Yamaha 2-Stroke and 4-Stroke 75–100 HP standard rotation lower units covered by the SE404 series. Not compatible with 2016 and newer 4-Stroke models ending in “B.”

Before you order, please verify:

• Engine model and model year
• Shaft length
• Gear ratio
• Rotation (SE404 = standard rotation)

Need help confirming fitment? Contact us for quick application assistance.

Yamaha® is a registered trademark of Yamaha Motor Co., Ltd. Use of the name is for reference only and does not imply affiliation or endorsement.