Mercury New Lower Unit 3 & 4 Cyl

Aftermarket Lower Unit for Mercury 3 & 4-Cylinder – Fits 70–125 HP 2-Stroke & 70–115 HP 4-Stroke (Serial # OT801000 and Below)

Looking for a reliable lower unit replacement for Mercury outboards? This remanufactured gearcase fits a wide range of Mercury models including 3 & 4-cylinder engines, covering 70–125 HP 2-Stroke and 75–115 HP 4-Stroke engines with serial numbers OT801000 and below. It’s an ideal solution for those searching for a Mercury lower unit interchange chart, Mercury 115 lower unit, or Mercury 125 lower unit alternatives.

Compatible with engine years from 1987 through present, this aftermarket non-OEM part is engineered for durability and performance. Backed by a 3–Year FAULT-FREE Warranty, it’s trusted by boaters seeking outboard lower unit replacement options without breaking the bank.

Whether you’re exploring the Mercury marine 115 HP 4-cylinder lower unit or other configurations, this unit provides a dependable fit and performance for most Mercury applications as stated above.

View our parts finder to find Mercury Outboard parts diagrams to verify this is a match or contact us using the buttons at the bottom of the page.

You can also use our parts finder to find other Mercury Boat Parts for your Mercury Outboard.

Get the right lower unit for your outboard when you call us today. Take the guess work out of ordering online.

Features & Benefits

• Replaces lower unit for Mercury 75, 90, 115, 125 hp, and more
• Fits: Mercury 3 & 4 Cylinder – 70–125 HP (2-Stroke), 70–115 HP (4-Stroke)
• Serial number compatibility: OT801000 and below (4-Stroke)
• Engine year coverage: 1987–2022
• Aftermarket – Non-OEM
• Backed by 3-Year FAULT-FREE Warranty

Pricing

Total Price: $1,195
Less $200 Core Rebate
Final Price: $995

Core Rebate Information

• Return your old core, get up to $200 back
• Rebate amount will vary based on the condition of your core
• ♻️ Recycle your core- keep boat parts out of the landfill

Useful Resources

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