250 HP – 4 Stroke Yamaha Counter Rotation

The SEI Sterndrive.cc Counter Rotation Lower Unit is specifically designed for Yamaha 250 HP 4-Stroke outboard motors, including models such as the Yamaha LF250XA, LF250XCA, LF250UCA, LF250XCB, and LF250UCB. This premium-quality lower unit is engineered to meet OEM standards, ensuring perfect fit, performance, and reliability.

Available with two precise gear ratio options (1.75:1 and 1.85:1) and shaft length variations (20-inch and 25-inch), this lower unit allows precise customization to match your exact motor configuration. The robust construction includes dual water pickups for improved cooling efficiency, especially in high-performance or offshore boating conditions.

This unit features a water-cooled bearing carrier, enhancing the durability of critical internal components by effectively managing operating temperatures. It comes standard in a corrosion-resistant black primer finish, ready to paint to match your Yamaha outboard’s original factory color.

Key Features:

• Compatible exclusively with Yamaha 250 HP 4-Stroke models: LF250XA, LF250XCA, LF250UCA, LF250XCB, LF250UCB
• Dual water pickup system for optimal cooling
• Water-cooled bearing carrier for enhanced durability
• Gear ratio options: 1.75:1 and 1.85:1
• Shaft lengths available: 20-inch and 25-inch
• Ready-to-paint black primer finish
• Specifically designed for counter rotation configurations

Technical FAQs:

Q1: Which Yamaha engine models is this lower unit specifically compatible with?
A: This lower unit is exclusively compatible with Yamaha 250 HP 4-Stroke engines, specifically models F250XA, LF250XCA, LF250UCA, LF250XCB, and LF250UCB.

Q2: How do I know the correct gear ratio for my Yamaha 250 HP 4-Stroke?
A: Refer to your motor’s OEM specifications: Yamaha LF250XA, LF250XCA, and LF250UCA typically use a 1.75:1 ratio, while Yamaha LF250XCB and LF250UCB commonly utilize a 1.85:1 ratio. Verify your exact motor’s specification in the owner’s manual.

Q3: Is this lower unit painted to match Yamaha factory colors?
A: The unit comes with a standard black primer finish, allowing you to paint it to precisely match your Yamaha outboard’s factory color.

Q4: Why does this lower unit feature dual water pickups?
A: Dual water pickups ensure efficient cooling even at high speeds or during aggressive boating maneuvers, minimizing overheating risks under demanding operating conditions.

Q5: What specific benefit does the water-cooled bearing carrier provide?
A: The water-cooled bearing carrier significantly reduces internal operating temperatures, extending component life and ensuring sustained performance during prolonged use.

Q6: Is this unit suitable for standard (clockwise) rotation setups?
A: No, this specific lower unit is designed solely for counter-rotation (counter-clockwise rotation) setups, typically required in twin-engine or multi-engine configurations for balanced thrust and improved handling.

Q7: Does this lower unit include seals and gaskets necessary for installation?
A: Yes, this lower unit comes complete with necessary seals and gaskets. However, verify compatibility and any additional hardware requirements specific to your engine model.

Q8: What is the warranty period provided with this SEI Sterndrive lower unit?
A: This SEI lower unit is backed by a 3-year fault-free warranty, providing comprehensive protection against manufacturer defects and workmanship.

Note: Some of the lower units may be on Back-order. Please confirm the ETA first by emailing, calling or texting us If you need it delivered soon.

Technical table for part number 90-429-B25F (2:1 gear ratio and 25″ drive shaft)

Technical table for part number 90-429-B30F (2:1 gear ratio and 30″ drive shaft)