SE416 Lower Unit – Fits Yamaha 150HP 4-Stroke & 150-225HP V6 2-Stroke
SE416 Lower Unit – Fits Yamaha 150HP 4-Stroke & 150-225HP V6 2-Stroke is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
SE416 Lower Unit – Fits Yamaha 150HP 4-Stroke & 150-225HP V6 2-...
SE416 Lower Unit – Fits Yamaha 150HP 4-Stroke & 150-225HP V6 2-Stroke is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket SE416 Lower Unit is designed as a complete gearcase replacement for a range of Yamaha outboard motors. It fits Yamaha V6 2-Stroke engines (150–225 HP, 1984–2012) and Yamaha F150 4-Stroke engines (150 HP, 2004–2024). This unit is configured for a 25-inch shaft length with a 2:1 gear ratio.
It directly replaces SEI part number 90-416-B25F and serves as an equivalent for Yamaha OEM part numbers in the 63P-45300-XX-8D supersession chain.
- Engineered for direct bolt-on installation.
- Arrives with the water pump pre-installed for convenience.
- Covered by a comprehensive 3-Year No-Fault Warranty.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| SEI | 90-416-B25F |
| Yamaha | 63P-45300-17-8D |
| Yamaha | 63P-45300-16-8D |
| Yamaha | 63P-45300-15-8D |
| Yamaha | 63P-45300-14-8D |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This lower unit is compatible with the following Yamaha 4-stroke and 2-stroke V6 models. Please verify your specific model and year.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F150XB2 | 150 | 4-Stroke | 2021–2024 | 63P-45300-XX-8D | |
| Yamaha | F150XB | 150 | 4-Stroke | 2015–2023 | 63P-45300-XX-8D | |
| Yamaha | F150XC/XC2 | 150 | 4-Stroke | 2024 | 63P-45300-XX-8D | |
| Yamaha | F150XA | 150 | 4-Stroke | 2012–2014 | 63P-45300-XX-8D | |
| Yamaha | F150TXR | 150 | 4-Stroke | 2006–2011 | 63P-45300-XX-8D | |
| Yamaha | F150TXRD | 150 | 4-Stroke | 2005 | 63P-45300-XX-8D | |
| Yamaha | F150TXRC | 150 | 4-Stroke | 2004 | 63P-45300-XX-8D | |
| Yamaha | F150XCB | 150 | 4-Stroke | 2024 | 63P-45300-XX-8D | |
| Yamaha | F150XSA/XSA2 | 150 | 4-Stroke | 2024 | 63P-45300-XX-8D | |
| Yamaha | Z200TXR | 200 | 2-Stroke | 2006–2012 | 64K-45300-02-NA | |
| Yamaha | Z150TXR | 150 | 2-Stroke | 2006–2009 | 64K-45300-02-NA | |
| Yamaha | Z175TXR(D) | 175 | 2-Stroke | 2005–2006 | 64K-45300-02-NA | |
| Yamaha | SX200TXR(C/D) | 200 | 2-Stroke | 2004–2005 | 64K-45300-02-NA | |
| Yamaha | Z200TXR(A/B/C/D) | 200 | 2-Stroke | 2002–2005 | 64K-45300-02-NA | |
| Yamaha | SX150TXR(A/B/C) | 150 | 2-Stroke | 2002–2004 | 64K-45300-02-NA | |
| Yamaha | V6 EXCEL | 150–200 | 2-Stroke | 1984–1989 | 64K-45300-02-NA | |
| Yamaha | VZ150TXR | 150 | 2-Stroke | 2006–2014 | 64K-45300-02-NA | VMAX Series |
| Yamaha | VZ150TLRD | 150 | 2-Stroke | 2005 | 64K-45300-02-NA | VMAX Series |
| Yamaha | VX150TXR(B/C) | 150 | 2-Stroke | 2002–2004 | 64K-45300-02-NA | VMAX Series |
| Yamaha | PROV150 | 150 | 2-Stroke | 1986–1990 | 64K-45300-02-NA | PRO-V Series |
Technical Specs
- Product Type
- Complete Lower Unit / Gearcase Assembly
- Installation
- Direct Bolt-on Replacement
- Gear Ratio
- 2:1
- Rotation
- Standard (Right Hand)
- Shaft Length
- 25 Inch
- Housing Material
- Marine-grade Aluminum
- Housing Color
- Black (Primer Finish)
- Approx. Dimensions
- 117 x 76 x 22 cm
- Weight
- 42.2 kg (93 lb)
- Warranty
- 3-Year No-Fault Warranty
- Included Components
- Pre-installed water pump
What’s in the Box
- 1 x Complete Lower Unit Assembly with pre-installed water pump
- 1 x Break-in Instructions
Installation Notes
- Ensure the engine is turned off and the key is removed. Disconnect the battery.
- Securely position the outboard motor in a tilted position to access the lower unit.
- Drain the gear lube from the existing lower unit completely.
- Unbolt and carefully remove the old lower unit assembly. You may need to disconnect the shift shaft.
- Clean the mating surfaces on the engine leg, ensuring they are free of old gasket material and corrosion.
- Align and install the new lower unit. Ensure the driveshaft splines, water tube, and shift shaft are correctly aligned.
- Bolt the new unit in place, tightening the bolts to the manufacturer's specified torque in a crisscross pattern.
- Fill the new gearcase with the recommended marine gear lube to the correct level.
- Reconnect the battery, start the engine using a water supply (flushing muffs), and check for proper water pump operation and shifting.
Troubleshooting & FAQ
How do I confirm this lower unit fits my Yamaha engine?
First, check your engine’s model number and year against our compatibility table. Second, confirm your existing unit has a 25" shaft length and a 2:1 or 1.86:1 gear ratio, as specified for the compatible models. If you are unsure, consult your service manual or a professional mechanic.
What else do I need for installation?
You will need to purchase marine-grade gear lube to fill the unit before operation. While not always required, we recommend a new installation gasket kit and potentially new mounting bolts, especially if the old ones show signs of corrosion or wear. Anode kits are also sold separately and should be replaced.
What maintenance is required after installation?
Follow the included break-in instructions carefully. After the break-in period (typically 10-20 hours), change the gear lube to remove any metal particles from the initial run-in. Thereafter, follow the maintenance schedule in your outboard's service manual.
What are signs my old lower unit is failing?
Common signs include a grinding or clunking noise when shifting or running, excessive vibration, metal shavings found in the gear lube (looks like metallic paint or glitter), water in the oil, or a persistent inability to shift into gear properly.
Is this an OEM part or aftermarket?
This is an aftermarket replacement part, not an original Yamaha (OEM) component. It has been manufactured in an ISO 9001 certified facility and engineered to meet or exceed OEM specifications using comparable materials and processes.
What is the shipping speed and cost?
We ship worldwide, with most orders arriving in 5–15 days via standard shipping. Standard shipping is typically free. If available for your location, expedited shipping options and their costs will be presented at checkout.
What is the warranty and return policy?
This part is covered by a 3-Year No-Fault Warranty against failures during normal use. If you experience an issue, please contact our support team with your order details for assistance. Returns for unused and uninstalled parts in their original condition are accepted within our standard return window.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
