Get reliable counter-rotation performance with this SEI 90-429 aftermarket lower unit, designed to replace Yamaha LF250 4-stroke outboards (2005–2018) with 25″ or 30″ driveshafts. This replacement unit supports both early and later models with dual or side water intakes and includes a water-cooled bearing carrier for added durability.
✅ For Counter Rotation Applications Only
✅ Replaces OEM LF250 lower units with 25″ or 30″ shafts
✅ Compatible with side and dual water intake models
✅ Painted black—can be color-matched to your engine
✅ Backed by a 1-Year Limited Warranty
Specification |
Details |
Product Name |
Yamaha 250HP 4-Stroke Counter Rotation Lower Unit |
Compatible Models |
LF250 Series |
Horsepower |
250HP |
Years Supported |
2005 – 2018 |
Gear Ratio |
2.00:1 |
Rotation |
Counter Rotation Only |
Shaft Lengths |
25″ & 30″ |
Water Intakes |
Dual & Side |
Driveshaft Type |
One-piece |
Color |
Black (Paintable) |
Warranty |
1 Year Limited |
OEM Replaces |
LF250XA, LF250TXR, LF250BTXR, LF250UA, LF250TUR, LF250BTUR, LF250TURD |
Part Codes |
90-429-B25F (25″), 90-429-B30F (30″) |
Installation |
Direct Fit – No Modifications Required |
Condition |
Brand New – Aftermarket |
David Flores –
The included gasket sealed perfectly—no leaks post-install. The unit shifts seamlessly and runs cooler than my old part. A hassle-free upgrade!
Cody Cannon –
Installed this on a 2005 motor—fit like a glove. Smooth engagement, no vibrations, and saved $700. Vintage boaters, this is your fix!
Alexander Mcfarland –
The customer team helped me troubleshoot a minor alignment issue over the phone. The unit itself is whisper-quiet, leak-free, and handles sudden throttle changes effortlessly. OEM quality without the insane markup!
Kelly Mendoza –
Thick housing—tough love!
Catherine Romero –
Installed this during a family fishing trip. Took 40 minutes, and it handled rough wakes without complaint. The kids noticed the quieter engine—thanks to this unit!
Phyllis Robertson –
After a $1,200 dealer quote, I gambled on this. Installed it myself in 45 minutes, saved $800, and gained smoother performance. Silent operation—why pay OEM prices?
Charles Brooks –
After a decade of OEM parts, I tried this. The stainless steel components are thicker, the shifts are faster, and the price is unbeatable. Why didn’t I switch sooner?
David Kline –
Pre-greased fittings saved me 30 minutes of messy work. Installed solo, and it’s been flawless through 50 hours of runtime. DIYers, this is your holy grail!
Charles Lane –
The delivery was so fast I thought it was a mistake. Installed the unit in 40 minutes, and it’s handled everything from idling to WOT without issue. Zero complaints!
Matthew Bailey –
The splines aligned perfectly on the first try. After eight weeks, the oil is still clear, and the unit runs silently. A flawless replacement!
Kelly Martin –
Vibration-free—smooth rides!
Shane Horn –
Eco-friendly packaging impressed my green-hearted crew. The unit handles heavy loads effortlessly—no complaints after 60 days. A planet-friendly choice for eco-conscious captains!
Jack Harrington –
Tested in Alaskan fjords and Caribbean reefs—no performance drop. The seals stay flexible in freezing temps, and shifts stay precise in tropical heat. A four-season workhorse!
Jared Dean –
24/7 support and leak-proof design—stellar product!
Kimberly Nguyen –
Quick email support resolved my query. Product is stellar!
Kayla Peterson –
I’ve put 20 hours on this unit since installation. The oil stays clean, the temperature stays steady, and there’s no vibration. Couldn’t ask for a better aftermarket solution!
Jacqueline Bullock –
This unit arrived with pre-filled gear lube and labeled hardware. Installed it during a rainstorm—still took under an hour. Shifts are seamless, and the anti-vibration design quiets the entire boat!
Jennifer Serrano –
I’ve recommended this to three friends already. The unit is robust, the shifts are seamless, and the oil stays contaminant-free. OEM quality without the markup!