Upgrade your Yamaha outboard’s performance with this SEI 423 aftermarket lower unit, built as a direct-fit replacement for F200–F300 models (2014–2021) with a 30″ driveshaft. Designed to match OEM specifications and engineered for durability, this lower unit offers a 1.75:1 gear ratio and fits single-piece driveshaft models without TERE (Thrust Enhancing Reverse Exhaust).
Fully assembled and ready to install
Direct OEM replacement—no modifications required
Compatible with Yamaha F250 & F300 4-stroke models
Painted black—can be repainted to match your engine
New aftermarket unit backed by a 1-year warranty
Replaces these OE #’s
6CE-45300-11-8D
6CE-45300-12-8D
6CE-45300-13-8D
6CE-45300-14-8D
6CE-45300-15-8D
Specification |
Details |
Product Name |
Yamaha F200–F300 4-Stroke Lower Unit |
Compatible Models |
F250UCA, F300UCA, F300BETU |
Horsepower Range |
200HP to 300HP |
Years Supported |
2014 – 2021 |
Gear Ratio |
1.75:1 |
Shaft Length |
30″ |
Driveshaft Type |
One-piece only (not for two-piece shafts) |
TERE Compatibility |
Not compatible with TERE |
Condition |
New – Aftermarket |
Color |
Black (paintable) |
Warranty |
1 Year |
OEM Replaces |
6CE-45300-11-8D, 12-8D, 13-8D, 14-8D, 15-8D |
Part Code / SKU |
90-423-B30F |
Installation |
Direct Fit – No Modifications Required |
Usage |
Freshwater & Saltwater Compatible |