Mercury Optimax DFI ECU | Part Number 858891T26 | Fits 2000 Mercury Optimax 200HP & 225HP 3.0L V6 | 1-Year Warranty

Product Overview

Replace your faulty engine control module with this genuine Mercury Optimax DFI ECU, Part Number 858891T26, designed for select 2000 Mercury Optimax 200HP and 225HP 3.0L V6 Direct Fuel Injection (DFI) outboard engines. This OEM Engine Control Unit (ECU) manages essential engine functions, including fuel delivery, ignition timing, and overall engine performance to ensure reliable operation. This unit has been professionally CDI tested and confirmed to be in proper working condition before being offered for sale. Removed from a running donor engine, it is an excellent replacement for a failed or damaged ECU and is supplied ready for installation. Backed by a 1-Year Warranty, this genuine Mercury ECU provides dependable performance and peace of mind.

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Key Features

• Genuine OEM Mercury Optimax ECU
• OEM Part Number: 858891T26
• Stamp Number: 8588918
• CDI Tested and Verified
• Ready for Installation
• Removed from Running Donor Engine
• No Cracks or Physical Damage
• 1-Year Warranty Included

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Technical Specifications

Specification	Details
Brand	Mercury
Product Type	Engine Control Unit (ECU)
Condition	Pre-Owned
OEM Part Number	858891T26
Stamp Number	8588918
Supersedes	85889126, 858891T1
Engine Type	Optimax 3.0L V6 DFI
Horsepower	200 HP / 225 HP
Model Year	2000

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Compatible Applications

Designed for select Mercury Optimax outboard engines including: Model Year

• 2000

Engine

• 3.0L V6 Direct Fuel Injection (DFI)

Horsepower

• 200 HP
• 225 HP

Donor Engine Serial Number

• 0T015387

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

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Condition

This is a genuine OEM Mercury Optimax ECU in excellent used condition. Before being offered for sale, the unit was:

• Professionally CDI tested
• Verified to be in proper working condition
• Removed from a running donor engine
• Inspected for physical damage
• Confirmed free of cracks and broken components
• Prepared for installation

The ECU hour log displays approximately 1,100 total hours. However, the recorded RPM-range breakdown totals approximately 270 hours, which is believed to more accurately reflect actual engine operation.

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What's Included

Your purchase includes:

• Mercury Optimax DFI ECU
• OEM Part Number 858891T26

No wiring harnesses, sensors, mounting hardware, or additional electronic components are included unless shown in the product photos.

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Shipping Information

Every ECU is carefully packaged to protect sensitive electronic components during transit. 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

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Warranty

This Mercury Optimax ECU is backed by a 1-Year Warranty. If the unit experiences a covered failure during normal recreational use 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 CDI Tested Electronics
• 1-Year Warranty Included
• Secure Packaging
• Fast Nationwide and International Shipping
• Competitive Pricing
• Experienced Customer Support
• Trusted Source for Outboard Motors and Marine Parts

EZ Boats Marine is committed to supplying dependable OEM marine components backed by knowledgeable customer service and reliable support.

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Frequently Asked Questions

Which engines does this ECU fit?

This ECU is designed for select 2000 Mercury Optimax 3.0L V6 DFI 200HP and 225HP outboard engines. Always verify your engine's serial number and OEM part number before ordering.

Has this ECU been tested?

Yes. The ECU has been professionally CDI tested and confirmed to be in proper working condition before sale.

Which part numbers does this ECU replace?

This ECU is compatible with the following Mercury part numbers:

• 858891T26
• 85889126
• 858891T1

Why are there different engine hour readings?

The ECU displays approximately 1,100 total hours, while the RPM-range hour breakdown totals approximately 270 hours. Based on the recorded data, the RPM-range breakdown is believed to more accurately reflect actual engine operation.

Does this ECU include a warranty?

Yes. This ECU is backed by a 1-Year Warranty, providing added confidence with your purchase.