Mercury Optimax Lower Unit | 20" Shaft | 2.07:1 Gear Ratio | Fits 2004 & Newer Mercury Optimax 75HP, 90HP & 115HP Outboards | 1-Year Warranty

Product Overview

Restore the performance of your Mercury outboard with this genuine Mercury Optimax Lower Unit, engineered for select 2004 and newer Mercury Optimax 75HP, 90HP, and 115HP outboard engines. Featuring a 20-inch shaft and 2.07:1 gear ratio, this professionally serviced OEM lower unit delivers dependable shifting, efficient power transfer, and long-lasting durability. Every lower unit is carefully inspected, fully resealed, pressure tested, and fitted with a new water pump impeller to ensure reliable performance on the water. Internal components are inspected under magnification, and OEM gears are retained whenever they meet Mercury's factory specifications. Ready for installation, this lower unit is backed by a 1-Year Warranty, making it an excellent choice for replacing a damaged or worn gearcase.

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Key Features

• Genuine OEM Mercury Optimax Lower Unit
• Fits Mercury Optimax 75HP, 90HP & 115HP Outboards
• 20-Inch Shaft
• 2.07:1 Gear Ratio
• Professionally Inspected
• Fully Resealed
• Pressure Tested
• New Water Pump Impeller Installed
• Internal Components Inspected Under Magnification
• OEM Gears Retained When Within Specification
• Ready for Installation
• 1-Year Warranty Included

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Technical Specifications

Specification	Details
Brand	Mercury
Product Type	Lower Unit
Condition	Professionally Serviced
Engine Compatibility	Mercury Optimax
Horsepower	75 HP / 90 HP / 115 HP
Model Years	2004 and Newer
Shaft Length	20 Inches
Gear Ratio	2.07:1
Driveshaft Length	20-3/4 Inches
Driveshaft Splines	13
Prop Shaft Splines	15

Driveshaft length is measured from the top of the water pump to the top of the driveshaft.

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Compatible Applications

Designed for select Mercury Optimax outboard engines including: Model Years

• 2004 and Newer

Horsepower

• 75 HP
• 90 HP
• 115 HP

Shaft Length

• 20-Inch (Long Shaft)

Gear Ratio

• 2.07:1

Important: Always verify your engine's model number, serial number, shaft length, gear ratio, and OEM part number before purchasing. If you need assistance confirming compatibility, our team is happy to help.

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Condition

This lower unit has been professionally serviced and thoroughly inspected before being offered for sale. Service and inspection include:

• Complete reseal
• Pressure tested to ensure leak-free performance
• New water pump impeller installed
• Internal components inspected under magnification
• OEM gears retained when they meet factory specifications
• Ready for installation

Please Note: Gear oil is not included and must be added before operating the lower unit.

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What's Included

Your purchase includes:

• Mercury Optimax Lower Unit Assembly
• New Water Pump Impeller
• Professionally Resealed and Pressure-Tested Gearcase

Only the components shown in the product photos are included.

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Shipping Information

Every lower unit is securely packaged to protect it during shipping. We offer fast shipping throughout the United States, with international shipping available upon request. For an accurate shipping quote, please provide:

• Country
• ZIP or Postal Code
• Commercial or Residential Address
• Whether liftgate service is required

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Warranty

This Mercury Optimax Lower Unit is backed by a 1-Year Warranty. If the lower unit experiences a covered failure during normal operation within the warranty period, EZ Boats Marine will repair, replace, or refund the item if a replacement is unavailable, in accordance with our warranty policy.

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Why Buy from EZ Boats Marine?

• Genuine OEM Mercury Marine Parts
• Professionally Serviced Lower Units
• Fully Resealed and Pressure Tested
• New Water Pump Impeller Installed
• OEM Internal Components
• 1-Year Warranty Included
• Secure Packaging
• Fast Nationwide and International Shipping
• Experienced Marine Customer Support

EZ Boats Marine is committed to supplying premium OEM marine components backed by dependable service, expert support, and reliable performance.

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Frequently Asked Questions

Which Mercury outboards does this lower unit fit?

This lower unit fits select 2004 and newer Mercury Optimax 75HP, 90HP, and 115HP outboards equipped with a 20-inch shaft and 2.07:1 gear ratio. Always verify your engine's model number, serial number, and OEM specifications before ordering.

Has this lower unit been serviced?

Yes. It has been professionally inspected, fully resealed, pressure tested, and fitted with a new water pump impeller before being offered for sale.

What is the gear ratio?

This lower unit features a 2.07:1 gear ratio, providing factory-correct performance for compatible Mercury Optimax outboards.

Is gear oil included?

No. Gear lubricant is not included and must be added before the lower unit is placed into service.

Does this lower unit include a warranty?

Yes. This Mercury Optimax Lower Unit is backed by a 1-Year Warranty, providing added confidence and peace of mind with your purchase.