SEI SE423 Yamaha Outboard Lower Unit 1.75:1 RatioThe SEI SE423 is an aftermarket replacement lower unit for select Yamaha outboards. Available in 25" and 30" shaft configurations, both versions feature a 1.75:1 gear ratio. Select the shaft length that matches your engine and confirm application before ordering.This item is subject to a 20% restocking fee.Year, serial number, and horsepower are required to process your order. Please contact us with this information after placing your order. Processing will be delayed until this information is received.Fitment 25" shaft 90-423-B25F: Fits select Yamaha F225, F250, F300, VF200, and VF250 applications.; 30" shaft 90-423-B30F: Fits select Yamaha F250 and F300 applications.; Does not fit engines originally built with two-piece driveshafts.; Does not fit engines equipped with TERE (Thrust Enhancing Reverse Exhaust).; Compatibility varies by engine model and year. Horsepower and shaft length alone do not confirm fitment.OEM Replacement References25" version: 6CE-45300-00-8D, 6CE-45300-01-8D, 6CE-45300-02-8D, 6CE-45300-03-8D, 6CE-45300-04-8D, and 6CE-45300-05-8D.30" version: 6CE-45300-11-8D, 6CE-45300-12-8D, 6CE-45300-13-8D, 6CE-45300-14-8D, and 6CE-45300-15-8D.Verify your existing lower unit part number and engine application before ordering.