Mercury Optimax Complete Ignition System | Part Number 858891T25 | Fits 1999–2001 Mercury Optimax 135HP & 150HP V6 DFI | 1-Year Warranty

Product Overview

Restore dependable ignition performance with this genuine Mercury Optimax Complete Ignition System, featuring ECU Part Number 858891T25. Designed for select 1999–2001 Mercury Optimax 135HP and 150HP V6 Direct Fuel Injection (DFI) outboard engines, this complete OEM ignition package includes the ECU, ignition coil, wiring harness, and associated components required to replace a damaged or malfunctioning ignition system. Each component has been professionally bench-tested and inspected to ensure proper operation before being offered for sale. Whether you're repairing an ignition failure or restoring your Optimax outboard, this complete assembly provides a reliable OEM replacement solution backed by a 1-Year Warranty.

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Key Features

• Genuine OEM Mercury Optimax Complete Ignition System
• ECU Part Number: 858891T25
• Complete Ignition Assembly
• Professionally Bench-Tested
• Cleaned and Inspected
• Connectors in Excellent Condition
• Ready for Installation
• 1-Year Warranty Included

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Technical Specifications

Specification	Details
Brand	Mercury
Product Type	Complete Ignition System
Condition	Pre-Owned
Engine Type	Optimax V6 Direct Fuel Injection (DFI)
Horsepower	135 HP / 150 HP
Model Years	1999–2001

Included OEM Part Numbers

• ECU / Power Pack: 858891T25
• Ignition Coil: 856991A1
• Wiring Harness: 858229T1
• Additional Components: 882751A1, 856624A2

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Compatible Applications

Designed for select Mercury Optimax outboard engines including: Model Years

• 1999
• 2000
• 2001

Horsepower

• 135 HP
• 150 HP

Engine

• V6 Direct Fuel Injection (DFI)

Important: Always verify your engine model number, serial number, and OEM part numbers before purchasing to ensure compatibility. If you need assistance confirming fitment, our team is happy to help.

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Condition

This is a genuine OEM Mercury Optimax complete ignition system in excellent used condition. Every major component has been professionally inspected and electrically bench-tested. Inspection includes:

• Electrical testing completed
• Windings verified within specification
• Connectors clean and undamaged
• No cracked housings
• No broken wiring
• No burnt insulation
• Ready for installation

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What's Included

Your purchase includes:

• Mercury Optimax ECU / Power Pack (858891T25)
• Ignition Coil (856991A1)
• Wiring Harness (858229T1)
• Additional OEM Components (882751A1 & 856624A2)

Only the components shown in the product photos are included.

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Shipping Information

Every ignition system is carefully packaged to protect sensitive electrical components during shipping. We offer secure 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

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Warranty

This Mercury Optimax Complete Ignition System is backed by a 1-Year Warranty. If any covered electrical component experiences a 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 Bench-Tested Electrical Components
• Complete OEM Ignition Assemblies
• 1-Year Warranty Included
• Secure Packaging
• Fast Nationwide and International Shipping
• Competitive Pricing
• Experienced Marine Customer Support

EZ Boats Marine is committed to providing dependable OEM marine parts and exceptional customer service to help keep your outboard performing at its best.

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Frequently Asked Questions

Which engines does this ignition system fit?

This complete ignition system is designed for select 1999–2001 Mercury Optimax 135HP and 150HP V6 DFI outboard engines. Always verify your engine's model number, serial number, and OEM part numbers before purchasing.

What components are included?

The package includes the ECU/Power Pack, ignition coil, wiring harness, and associated OEM components listed in the specifications.

Has the ignition system been tested?

Yes. All major electrical components have been professionally bench-tested and inspected to verify proper operation before sale.

Is this a genuine Mercury ignition system?

Yes. This is a genuine OEM Mercury Optimax ignition assembly using original Mercury components.

Does this ignition system include a warranty?

Yes. The complete ignition system is backed by a 1-Year Warranty, providing added confidence with your purchase.