Mercury Lower Unit | 15" Shaft | Fits 1980–1994 Mercury 18HP, 20HP & 25HP 2-Cylinder 2-Stroke Outboards | 1-Year Warranty

Product Overview

Restore dependable performance to your Mercury outboard with this genuine Mercury 15-Inch Lower Unit, designed for select 1980–1994 Mercury 18HP, 20HP, and 25HP 2-cylinder 2-stroke outboard engines. Built to OEM specifications, this professionally serviced lower unit is an ideal replacement for damaged, leaking, or worn gearcases. Every lower unit is completely disassembled, carefully inspected, fully resealed, and pressure tested to ensure reliable operation. A new water pump impeller is installed during servicing, while internal components are inspected under magnification. OEM gears are retained whenever they meet Mercury factory specifications, providing dependable shifting and long service life. The housing has also been professionally stripped and primed, making it ready for paint or installation. Backed by a 1-Year Warranty, this lower unit is ready to get your Mercury outboard back on the water.

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Key Features

• Genuine OEM Mercury Lower Unit
• Fits Mercury 18HP, 20HP & 25HP 2-Stroke Outboards
• Designed for 2-Cylinder Engines
• 15-Inch Shaft
• Professionally Inspected
• Fully Resealed
• Pressure Tested
• New Water Pump Impeller Installed
• Internal Components Inspected Under Magnification
• OEM Gears Retained When Within Specification
• Housing Professionally Stripped and Primed
• Ready for Paint or Installation
• 1-Year Warranty Included

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Technical Specifications

Specification	Details
Brand	Mercury
Product Type	Lower Unit
Condition	Professionally Serviced
Engine Type	2-Cylinder 2-Stroke
Shaft Length	15 Inches
Horsepower	18 HP / 20 HP / 25 HP
Model Years	1980–1994
Driveshaft Length	15-7/8 Inches
Driveshaft Splines	9
Prop Shaft Splines	10

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 outboard engines including: Model Years

• 1980–1994

Horsepower

• 18 HP
• 20 HP
• 25 HP

Engine Type

• 2-Cylinder
• 2-Stroke

Shaft Length

• 15-Inch

Important: Always verify your engine's model number, serial number, shaft length, 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 disassembly and inspection
• Internal components inspected under magnification
• Fully resealed
• Pressure tested to ensure leak-free performance
• New water pump impeller installed
• OEM gears retained when they meet factory specifications
• Housing professionally stripped and primed
• Ready for paint or 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 15-Inch 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 15-Inch 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
• Housing Professionally Stripped and Primed
• 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 1980–1994 Mercury 18HP, 20HP, and 25HP 2-cylinder 2-stroke outboards with a 15-inch shaft. Always verify your engine's model number, serial number, and OEM part number before ordering.

Has this lower unit been professionally serviced?

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

Is the housing painted?

No. The housing has been professionally stripped and primed, allowing you to apply your preferred finish before installation if desired.

Is gear oil included?

No. Gear lubricant is not included and must be added before operating the lower unit.

Does this lower unit include a warranty?

Yes. This Mercury 15-Inch Lower Unit is backed by a 1-Year Warranty, providing added confidence and peace of mind with your purchase.