Mercury V6 Lower Unit 859399T14

New OEM Mercury Marine Lower Unit – 3.0L V6 | 25″ XL Shaft | Standard Rotation – #859399T14

Fits: Mercury 200, 225, 250 HP V6 Outboards | 3.0 Liter | OEM Part #859399T14 | XL 25” Shaft

This brand-new Mercury OEM lower unit, part number 859399T14, is a direct replacement for select Mercury 3.0L 6-cylinder V6 outboard motors with XL shaft. Designed for standard right-hand rotation, this genuine Mercury Marine product ensures factory-spec performance, seamless fitment, and long-term reliability for Mercury V6 engines rated at 200 HP, 225 HP, and 250 HP.

Built to Mercury’s exacting standards, this OEM (not aftermarket) lower unit is engineered with high-grade materials for unmatched durability and smoother operation. Perfect for performance boats, fishing boats, or commercial operators relying on dependable thrust and handling.

This unit comes with a 1-Year Manufacturer Warranty and is eligible for a $200 rebate upon the return of a good, rebuildable core—bringing your final cost to just $2,995.

Whether you’re replacing a damaged gearcase or upgrading from a worn-out lower unit, this Mercury V6 lower unit delivers the performance and OEM assurance you demand.

Fits/Specs

• Engine Type: Mercury 3.0L V6 6-Cylinder
• Horsepower: 200 HP, 225 HP, 250 HP
• Shaft Length: XL – 25″ Shaft
• OEM Part Number: 859399T14 / 1623-859399T14
• Compatible Models: Mercury V6 outboards using OEM# 859399T14
• Other Shaft Sizes Available: L, 20″ 

Pricing

Retail Price: $3,414

Our Price: $3,195 before core rebate
Potential Core Rebate: $200
Final Price $2,995

Product Finish:

• OEM factory-coated in corrosion-resistant Mercury black
• Genuine Mercury Marine assembly
• Built for long-term saltwater and freshwater performance

Core Rebate Information

• ♻️ Ask about how to recycle your core & receive $ back
• Return your old core, get up to $200 back
• Rebate amounts vary based on condition of your core

Useful Resources

• 🔍 How to find your Boat Engine serial number
• Still deciding? Watch our YouTube video How avoid common lower unit replacement mistakes
• To help extend the life of your gearcase, check out our Boat Maintenance Checklist