Original price was: $1,330.89.$1,199.00Current price is: $1,199.00.
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Manufacturer Warranty: 3-Year
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Return Policy: 60-day, hassle-free returns
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Trusted by 6,000+ boaters across the USA
The SEI 90-405 is a high-quality aftermarket replacement lower unit for Yamaha outboard engines in the 115–130HP range. Compatible with both 2-stroke and 4-stroke models, this standard rotation lower unit fits 20″ and 25″ shaft lengths. Designed to match performance and durability, it replaces multiple Yamaha OEM lower units from 1984 to 2014.
The unit comes painted in black and can be repainted to match your motor’s original color.
| Model | Details |
|---|---|
| Unit | SEI 90-405 |
| Rotation | Standard |
| Fits | Yamaha 115–130HP 2-Stroke & 2000–2014 F115 4-Stroke |
| Compatible Years | 1984–2014 |
| Shaft Lengths | 20″ & 25″ |
| Gear Ratios | 2:1 (2-Stroke), 2.15:1 (F115 4-Stroke) |
| Paint | Black (can be painted to match) |
| Warranty | 3-Year |
| Weight | 65 lbs |
|---|---|
| Dimensions | 37 × 10 × 61 in |
| Ratio/Shaft |
2:1 Ratio / 20" Shaft / 2 Stroke / RH Rotation ,2:1 Ratio / 25" Shaft / 2 Stroke / RH Rotation ,2.15:1 Ratio / 20" Shaft / 4 Stroke / RH Rotation ,2.15:1 Ratio / 25" Shaft / 4 Stroke / RH Rotation |
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Jerry Reynolds –
All-season reliability—versatile pick!
Amanda Davis –
The splines slid into place with zero hassle. After a month, the unit shows no wear and performs like new. A flawless, budget-friendly replacement!
John Stevens –
The splines fit snugly—no play or vibration. After 30 hours, the unit runs silently and cool. A flawless replacement for half the OEM cost!
Donna Kelly –
I’ve used this for six fishing trips now, including rough offshore conditions. It handles sudden throttle changes without hesitation, and there’s no play in the prop shaft. Feels like a factory part!
Travis Turner –
Followed the manual—done in 20 minutes. No complaints!
Lori Rodriguez –
Excel in tournaments and leisure. Unbeatable value!
Karen Thompson –
No special tools needed. Done in a coffee break!
Todd Richardson –
Quick support—durable choice!
Erik Hampton –
No leaks—trusty upgrade!
Robert Reid –
Instant joy—buy now!
Michael Watson –
24/7 support and a leak-proof guarantee—stellar combo. The unit arrived early, runs quiet, and handles hurricane swells. A standout in aftermarket parts!
Ariel Woods –
Eco-packaging—heavy loads conquered!
Julie Thomas –
This unit arrived with a protective film on the housing—nice touch. Installation took 40 minutes, and performance is whisper-quiet. Worth every penny for peace of mind!
Laurie Oneal –
The pre-greased fittings saved me time during installation. After 25 hours of runtime, the unit performs like new. A must-buy for practical boaters!
Thomas Carson –
The unit arrived with a handwritten thank-you card. Installed it in 25 minutes, and performance is flawless. OEM quality without the markup—zero buyer’s remorse!
Scott Patrick –
Not a single leak. Performs like it’s brand new.
Kristina Gomez –
Tested this in saltwater estuaries for weeks—zero rust on the stainless steel components. Shifts are crisp, the oil stays clean, and the price beats OEM by half. A saltwater angler’s dream!
Julie Webb –
Matched my engine perfectly. Installation was a cakewalk!
Albert Pittman –
Thank-you card—classy touch. Flawless performance!
Cindy Baird –
The splines aligned perfectly—no adjustments needed. After two months, the unit runs cooler and quieter than my OEM part. A budget-friendly gem with premium performance!
David Chandler –
Thick housing—tough love!
Roger Hunter –
The anti-corrosion coating is military-grade. After saltwater immersion, it looks pristine. Shifts are silent, the price is fair, and delivery was overnight. A saltwater boater’s best friend!
Kyle Black –
No downtime—quick swap!
Daniel Woodward –
After months of hesitation, I finally replaced my old unit with this model. The installation took 40 minutes with basic tools, and it’s been leak-free through 20+ fishing trips. Smooth shifts and no corrosion—worth every penny!
Marc Thomas –
No guesswork—clear labels and diagrams. Works like OEM!
Steven Lee –
Eco-friendly packaging impressed me. The unit handles heavy loads effortlessly—no complaints after 60 days. A green choice for eco-conscious boaters!
Ryan Deleon –
After a flawed Amazon unit, this saved my season. Crisp shifts, bone-dry seals, stellar service. Finally, a company that cares about boaters!
Jennifer Brown –
The anti-vibration design reduces cockpit noise significantly. Installed it in 45 minutes, and shifts are buttery-smooth. Premium feel without the premium price!