Lower Unit Assembly - Fits Yamaha V6 2.6L 2-Stroke Outboards (Replaces 64D-45300-24-8D)

Product Details

This SEI Marine replacement Lower Unit Assembly - Fits Yamaha V6 2.6L 2-Stroke Outboards (Replaces 64D-45300-24-8D) is engineered for Yamaha 90-degree V6 2.6L 2-stroke outboards requiring a standard (right-hand) rotation, 25-inch shaft, and a 1.86:1 gear ratio. It covers a wide range of models manufactured between 1984 and 2012.

It serves as a direct cross-reference for Yamaha part numbers 64D-45300-24-8D and 64D-45300-23-8D, as well as SEI Marine's 90-416-A25 aftermarket equivalent.

• Installation: Designed as a direct bolt-on replacement for a hassle-free swap.
• Warranty: Backed by a comprehensive 3-Year No-Fault Warranty for peace of mind.
• Engine Fitment: Built for Yamaha V6 2.6L outboards from 150 HP to 225 HP.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This lower unit is compatible with the following Yamaha V6 2.6L 2-stroke models.

Technical Specs

Product Type

Outboard Lower Unit Assembly

Installation

Direct bolt-on replacement

Gear Ratio

1.86:1

Rotation

RH (Standard)

Shaft Length

25"

Engine Type

Yamaha 2-Stroke V6 2.6 Liter

Compatible Engine HP

150-225 HP

Housing Color

Black (may vary based on inventory)

Product Dimensions (L x W x H)

78.0 x 23.0 x 130.0 cm

Box Dimensions (L x W x H)

78.0 x 23.0 x 130.0 cm

Warranty

3-Year No-Fault Warranty

What’s in the Box

• 1 x Lower Unit Assembly (equivalent to 64D-45300-24-8D)

Installation Notes

1. Drain the existing gear lube from your current lower unit.
2. Disconnect and remove the old lower unit assembly from the outboard midsection.
3. Clean the mating surfaces and inspect the driveshaft splines for wear.
4. Apply a light coating of marine grease to the driveshaft splines before installation.
5. Carefully align the new lower unit, ensuring the driveshaft, shift shaft, and water tube are properly seated.
6. Secure the new unit with the correct mounting bolts, tightening them to the manufacturer's specified torque sequence.
7. Refill the new lower unit with the recommended gear lube to the proper level.

Note: Always refer to your engine's official service manual for detailed procedures and torque specifications. It is highly recommended to replace the water pump impeller during installation.

Troubleshooting & FAQ

Safety & Important Info

• Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
• Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.