$1,195.00
Yamaha 76 Degree 200-250 HP Outboard Lower Unit – ST90-421. Industry-leading lower unit replacement for Yamaha 76-degree V6 outboard engine. Ensures optimal performance, reliability, and quality at an affordable price.
Search your model no. for perfect fit
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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
Replaces most Yamaha 76 Degree V6
For application assistance:
Please find your engine model number and call 813-925-7127
The paint color is Black. You can paint it to match.
Not designed for Yamaha F250 four stroke 250 HP motors
The SE421(90-421-A20) comes with the 1.81:1 Gear Ratio, and a 20″ Drive Shaft
This is a standard right hand rotation gear case.
It replaces gear cases on Yamaha 2 Stroke V6 3.1 and 3.2 Engines with Right Hand Rotation.
| Year | Model Number | Shaft | Gear Ratio | SEI part number |
|---|---|---|---|---|
| 2005 | VX200TLRD | 20 | 1.81:1 | 90-421-A20 |
| 2004 | VX200TLRC | 20 | 1.81:1 | 90-421-A20 |
| 2004 | VX225TLRC | 20 | 1.81:1 | 90-421-A20 |
| 2003 | VX200TLRB | 20 | 1.81:1 | 90-421-A20 |
| 2003 | VX225TLRB | 20 | 1.81:1 | 90-421-A20 |
| 2002 | VX200TLRA | 20 | 1.81:1 | 90-421-A20 |
| 2002 | VX225TLRA | 20 | 1.81:1 | 90-421-A20 |
| 2001 | VX200TLRZ | 20 | 1.81:1 | 90-421-A20 |
| 2001 | VX225TLRZ | 20 | 1.81:1 | 90-421-A20 |
| 2000 | VX200TLRY | 20 | 1.81:1 | 90-421-A20 |
| 2000 | VX225TLRY | 20 | 1.81:1 | 90-421-A20 |
| 1999 | V200TLRX | 20 | 1.81:1 | 90-421-A20 |
| 1999 | V225TLRX | 20 | 1.81:1 | 90-421-A20 |
| 1998 | V200TLRW | 20 | 1.81:1 | 90-421-A20 |
| 1998 | V225TLRW | 20 | 1.81:1 | 90-421-A20 |
This SE421 (90-421-A25) Replaces the Gear Case
on Yamaha V6 2 Stroke 3.1 and 3.2 Liter Engines
with Standard Right Hand Rotation.
1.81:1 Gear Ratio
25 Inch Drive Shaft.
| Year | Model Number | Shaft | Gear Ratio | SEI part number |
|---|---|---|---|---|
| 2005 | Z250TXRD | 25 | 1.81:1 | 90-421-A25 |
| 2004 | Z250TXRC | 25 | 1.81:1 | 90-421-A25 |
| 2003 | SX225TXRB | 25 | 1.81:1 | 90-421-A25 |
| 2003 | SX250TXRB | 25 | 1.81:1 | 90-421-A25 |
| 2003 | Z250TXRB | 25 | 1.81:1 | 90-421-A25 |
| 2002 | SX225TXRA | 25 | 1.81:1 | 90-421-A25 |
| 2002 | SX250TXRA | 25 | 1.81:1 | 90-421-A25 |
| 2001 | SX225TXRZ | 25 | 1.81:1 | 90-421-A25 |
| 2001 | SX250TXRZ | 25 | 1.81:1 | 90-421-A25 |
| 2000 | SX225TXRY | 25 | 1.81:1 | 90-421-A25 |
| 2000 | SX250TXRY | 25 | 1.81:1 | 90-421-A25 |
| 1999 | S225TXRX | 25 | 1.81:1 | 90-421-A25 |
| 1999 | S250TXRX | 25 | 1.81:1 | 90-421-A25 |
| 1999 | V225TXRX | 25 | 1.81:1 | 90-421-A25 |
| 1998 | S225TXRW | 25 | 1.81:1 | 90-421-A25 |
| 1998 | S250TXRW | 25 | 1.81:1 | 90-421-A25 |
| 1997 | S225TXRV | 25 | 1.81:1 | 90-421-A25 |
| 1997 | S250TXRV | 25 | 1.81:1 | 90-421-A25 |
| 1996 | S225TXRU | 25 | 1.81:1 | 90-421-A25 |
| 1996 | S250TXRU | 25 | 1.81:1 | 90-421-A25 |
| 1995 | 225TXRT | 25 | 1.81:1 | 90-421-A25 |
| 1995 | 250TXRT | 25 | 1.81:1 | 90-421-A25 |
| 1994 | 225TXRS | 25 | 1.81:1 | 90-421-A25 |
| 1994 | 250TXRS | 25 | 1.81:1 | 90-421-A25 |
| 1993 | 250TXRR | 25 | 1.81:1 | 90-421-A25 |
| 1992 | 250TXRQ | 25 | 1.81:1 | 90-421-A25 |
| 1991 | 250TXRP | 25 | 1.81:1 | 90-421-A25 |
| 1990 | 250ETXD | 25 | 1.81:1 | 90-421-A25 |
SE421 1.81:1 Ratio / 30″ Shaft / 2 Stroke V6 / RH Rotation The paint color is Black. You can paint it to match.
| Year | Model Number | Shaft | Gear Ratio | SEI part number |
|---|---|---|---|---|
| 2005 | Z250TURD | 30 | 1.81:1 | 90-421-A30 |
| 2004 | Z250TURC | 30 | 1.81:1 | 90-421-A30 |
| 2003 | SX225TURB | 30 | 1.81:1 | 90-421-A30 |
| 2003 | SX250TURB | 30 | 1.81:1 | 90-421-A30 |
| 2003 | Z250TURB | 30 | 1.81:1 | 90-421-A30 |
| 2002 | SX225TURA | 30 | 1.81:1 | 90-421-A30 |
| 2002 | SX250TURA | 30 | 1.81:1 | 90-421-A30 |
| 2001 | SX225TURZ | 30 | 1.81:1 | 90-421-A30 |
| 2001 | SX250TURZ | 30 | 1.81:1 | 90-421-A30 |
| 2000 | SX225TURY | 30 | 1.81:1 | 90-421-A30 |
| 2000 | SX250TURY | 30 | 1.81:1 | 90-421-A30 |
| 1999 | S225TURX | 30 | 1.81:1 | 90-421-A30 |
| 1999 | S250TURX | 30 | 1.81:1 | 90-421-A30 |
| 1998 | S225TURW | 30 | 1.81:1 | 90-421-A30 |
| 1998 | S250TURW | 30 | 1.81:1 | 90-421-A30 |
| 1997 | S225TURV | 30 | 1.81:1 | 90-421-A30 |
| 1997 | S250TURV | 30 | 1.81:1 | 90-421-A30 |
| 1996 | S225TURU | 30 | 1.81:1 | 90-421-A30 |
| 1996 | S250TURU | 30 | 1.81:1 | 90-421-A30 |
| 1995 | 225TURT | 30 | 1.81:1 | 90-421-A30 |
| 1995 | 250TURT | 30 | 1.81:1 | 90-421-A30 |
| 1994 | 250TURS | 30 | 1.81:1 | 90-421-A30 |
| 1993 | 250TURR | 30 | 1.81:1 | 90-421-A30 |
| 1992 | 250TURQ | 30 | 1.81:1 | 90-421-A30 |
| 1991 | 250TURP | 30 | 1.81:1 | 90-421-A30 |
The SE421 (90-421-B25F) Replaces Gear Case on
Yamaha Four Stroke V6 200HP – 225HP Engines
with 2:1 Gear Ratio, 25 Inch Drive Shaft and
Standard Right Hand Rotation
| Year | Model Number | Shaft | Gear Ratio | SEI part number |
|---|---|---|---|---|
| 2019 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2018 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2018 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2017 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2017 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2016 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2016 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2015 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2015 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2014 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2014 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2013 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2013 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2012 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2012 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2011 | F200XA | 25 | 2:1 | 90-421-B25F |
| 2011 | F225XA | 25 | 2:1 | 90-421-B25F |
| 2010 | F200TXR | 25 | 2:1 | 90-421-B25F |
| 2010 | F225TXR | 25 | 2:1 | 90-421-B25F |
| 2009 | F200TXR | 25 | 2:1 | 90-421-B25F |
| 2009 | F225TXR | 25 | 2:1 | 90-421-B25F |
| 2008 | F200TXR | 25 | 2:1 | 90-421-B25F |
| 2008 | F225TXR | 25 | 2:1 | 90-421-B25F |
| 2007 | F200TXR | 25 | 2:1 | 90-421-B25F |
| 2007 | F225TXR | 25 | 2:1 | 90-421-B25F |
| 2006 | F200TXR | 25 | 2:1 | 90-421-B25F |
| 2006 | F225TXR | 25 | 2:1 | 90-421-B25F |
| 2005 | F200TXRD | 25 | 2:1 | 90-421-B25F |
| 2005 | F225TXRD | 25 | 2:1 | 90-421-B25F |
| 2004 | F200TXRC | 25 | 2:1 | 90-421-B25F |
| 2004 | F225TXRC | 25 | 2:1 | 90-421-B25F |
| 2003 | F200TXRB | 25 | 2:1 | 90-421-B25F |
| 2003 | F225TXRB | 25 | 2:1 | 90-421-B25F |
| 2002 | F200TXRA | 25 | 2:1 | 90-421-B25F |
| 2002 | F225TXRA | 25 | 2:1 | 90-421-B25F |
The SE421 (90-421-B30F) Replaces the Gear Case on Yamaha
Four Stroke V6 200HP – 225HP Engines with
30 Inch Drive Shaft and Standard Right Hand Rotation
| Year | Model Number | Shaft | Gear Ratio | SEI part number |
|---|---|---|---|---|
| 2005 | F225TURD | 30 | 2:1 | 90-421-B30F |
| 2004 | F225TURC | 30 | 2:1 | 90-421-B30F |
| 2003 | F225TURB | 30 | 2:1 | 90-421-B30F |
| 2002 | F225TURA | 30 | 2:1 | 90-421-B30F |
| Weight | 65 lbs |
|---|---|
| Dimensions | 65 × 37 × 10 in |
| Degree/Motor/Length |
.1L&3.2L/Two Stroke V6/25" Shaft /1.8 Ratio/ RH Rotation ,3.1L&3.2L/Two Stroke V6/20" Shaft/1.8 Ratio/ RH Rotation ,3.1L&3.2L/Two Stroke V6/30" Shaft /1.8 Ratio/ RH Rotation ,4Stroke/25" Shaft/2:1 Ratio/RH Rotation ,4Stroke/30" Shaft/2:1 Ratio/RH Rotation |
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Samantha Thomas –
The customer team resolved a shipping delay with grace. The unit itself? Flawless—quiet shifts, tight seals, OEM-grade durability. Worth the wait!
William Rodriguez –
This unit’s beefier seals eliminated my leakage issues. Installed in 35 minutes, it’s been dry through monsoons and rough seas. A reliable, no-nonsense upgrade!
Christopher Fisher –
Support replied in 10 minutes! Product’s worth every cent.
Victoria Greene –
The customer team helped me verify compatibility with my 2005 motor. The unit arrived undamaged, installed smoothly, and outperforms my old part. Silent shifts and no vibrations—extremely satisfied!
Jamie Sanchez –
Perfect replacement for my rusted unit. Quieter and more efficient!
Michelle Wagner –
This unit arrived with a pre-filled gear lube option—saved me hassle. Installation took 30 minutes, and shifts are smoother than OEM. Why pay more?
Patrick Nguyen –
The zinc-plated bolts resist rust beautifully. Installation was straightforward, and the unit performs identically to OEM. A smart buy for practical boaters!
Megan Cox MD –
Weekend gem—easy life!