New Yamaha 200–250HP 2/4-Stroke (1990–2019) Replacement Lower Unit | Aftermarket | Counter Rotation | Fits 25″ & 30″ Shafts | 3-Year Warranty
Original price was: $1,552.89.$1,399.00Current price is: $1,399.00.
New Yamaha F75–100 | F75/90A 4-Stroke (1999–2017) Replacement Lower Unit | Aftermarket | Fits 20″ & 25″ Shafts | New or Remanufactured | 1-Year Warranty
Original price was: $2,685.09.$2,299.00Current price is: $2,299.00.
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New Yamaha 250HP 4-Stroke (2005–2018) Counter-Rotation Replacement Lower Unit Aftermarket | Fits 25″ & 30″ Shafts | 2.00 Gear Ratio | 1-Year Warranty
Original price was: $1,921.90.$1,699.00Current price is: $1,699.00.
Need help finding the right lower unit?
- Unsure about compatibility? Our team can verify the perfect fit for your Yamaha model.
- Call us at 888 868 7880 — we’re happy to guide you.
- Or fill out the form below in chatbox and we’ll respond quickly with the right match.
Description
Enhance the performance and reliability of your Yamaha LF250 4-Stroke outboard with this high-quality aftermarket counter-rotation lower unit from SEI Marine Products. Engineered for precision, smooth operation, and long-lasting durability — this replacement gearcase delivers OEM-level performance for Yamaha 250HP engines manufactured between 2005 and 2018.
Key Features
- Perfect Fit for Yamaha LF250 Outboards
Designed specifically for counter-rotation (left-hand) applications on Yamaha LF250 4-Stroke engines. Direct-fit installation means no modifications are needed — simply bolt on and go. - Dual & Side Water Intake Compatibility
Supports both early-model side intakes and later-model dual water intakes, ensuring consistent cooling across all conditions. - Built for Strength & Longevity
Features a one-piece driveshaft, precision-cut gears, and a water-cooled bearing carrier for reduced friction, longer life, and smoother gear engagement. - OEM-Like Finish
Finished in durable black paint that can be repainted to match your Yamaha factory color for a clean, professional look. - Reliable Performance Assurance
Tested for strength and endurance, this lower unit is backed by a 1-Year Limited Warranty — delivering confidence and peace of mind on every trip.
Specifications
| Feature | Details |
|---|---|
| Horsepower | 250HP |
| Compatible Models | Yamaha LF250 4-Stroke (Counter Rotation) |
| Years Covered | 2005 – 2018 |
| Gear Ratio | 2.00:1 |
| Rotation | Counter (Left-Hand) |
| Shaft Lengths | 25″ & 30″ |
| Water Intakes | Dual & Side Compatible |
| Driveshaft Type | One-Piece |
| Finish | Black (Paintable to Match OEM) |
| Condition | 100% Brand New – Aftermarket |
| Warranty | 1-Year Limited |
| OEM Replaces | LF250XA, LF250TXR, LF250UA, LF250TUR, LF250BTXR, LF250BTUR, LF250TURD |
| Part Numbers | 90-429-B25F (25″), 90-429-B30F (30″) |
| Installation | Direct Fit – No Modifications Required |
Why Choose This Yamaha 250HP Counter Rotation Lower Unit?
This SEI replacement lower unit is a complete, factory-assembled, brand-new gearcase — not remanufactured or rebuilt. It arrives ready to install, pre-filled with quality components, and pressure-tested for performance. Perfect for restoring or upgrading your twin-engine Yamaha setup, it provides smooth handling, strong torque, and dependable counter-rotation control in any marine environment.
- Designed for Yamaha 250HP LF250 4-Stroke outboards (2005–2018)
- 100% brand new, not remanufactured
- Direct OEM-fit design — no modifications required
- Backed by SEI’s trusted 1-year warranty
Frequently Asked Questions – Yamaha 250HP 4-Stroke Counter Rotation Replacement Lower Unit
1. Which Yamaha outboard models is the SEI 90-429 counter rotation lower unit compatible with?
The SEI 90-429 fits Yamaha LF250 4-Stroke outboards manufactured between 2005 and 2018. It supports counter (left-hand) rotation and is a direct-fit replacement for models including LF250XA, LF250TXR, LF250UA, LF250TUR, LF250BTXR, LF250BTUR, and LF250TURD.
2. What shaft lengths and gear ratio does this lower unit offer?
This unit is available with 25″ and 30″ shaft lengths, both featuring a 2.00:1 gear ratio. These specifications maintain OEM performance standards to optimize torque, speed, and efficient propeller operation.
3. What design features enhance durability and cooling in this lower unit?
The lower unit includes a one-piece driveshaft with precision-cut gears and a water-cooled bearing carrier to reduce friction and extend component life. It accommodates both dual and side water intakes for efficient cooling in varied aquatic environments.
4. Is the SEI 90-429 lower unit ready to install out of the box?
Yes, this unit arrives fully assembled, pre-filled with premium gear lube, and painted black with a paintable surface for easy OEM color matching. Installation requires no modifications—simply bolt on for a seamless replacement.
5. What warranty coverage does the SEI 90-429 lower unit provide?
SEI backs this aftermarket replacement with a 1-Year Limited Warranty covering defects in materials and workmanship, providing confidence in the durable construction and reliable operation of the unit.
Looking for Other Yamaha Models or Rotations?
Browse all Yamaha Lower Units — including standard and counter-rotation options for 75HP, 150HP, 200HP, and 300HP Yamaha outboards.
Additional information
| Weight | 90 lbs |
|---|---|
| Dimensions | 23 × 13 × 31 in |
| Ratio/Shaft |
F250/ 25" Shaft/ 2.00/4 Stroke ,F250/ 30" Shaft/ 2.00/4 Stroke |
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