Mercury Optimax DFI ECU | Part Number 858891T29 | Fits 2000 Mercury Optimax 200HP & 225HP 3.0L V6 | 1-Year Warranty

Product Overview

Restore the performance of your Mercury Optimax outboard with this genuine Mercury Optimax DFI Engine Control Unit (ECU), Part Number 858891T29. Designed for select 2000 Mercury Optimax 200HP and 225HP 3.0L V6 Direct Fuel Injection (DFI) outboard engines, this OEM ECU controls critical engine management functions, including fuel delivery, ignition timing, and overall engine performance. This ECU has been professionally bench-tested, cleaned, and inspected to verify proper operation before being offered for sale. It is an excellent replacement for a faulty or damaged control module and is supplied ready for installation. Backed by a 1-Year Warranty, this OEM Mercury ECU provides dependable performance and confidence on the water.

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Key Features

• Genuine OEM Mercury Optimax ECU
• OEM Part Number: 858891T29
• Supersedes Part Number: 85889129
• Bench-Tested for Proper Operation
• Professionally Cleaned and Inspected
• Connectors Clean and Intact
• No Cracks or Broken Wiring
• Ready for Installation
• 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	858891T29
Superseded Part Number	85889129
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

Important: Always verify your engine's model number, serial number, and OEM part number before ordering. 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 bench-tested
• Cleaned and inspected
• Verified to have clean, undamaged electrical connectors
• Confirmed free of cracks and broken wiring
• Prepared for installation

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What's Included

Your purchase includes:

• Mercury Optimax DFI ECU
• OEM Part Number 858891T29

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 Tested Electronic Components
• 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 providing dependable OEM marine components backed by quality service and reliable customer 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 OEM part number and engine serial number before purchasing.

Has this ECU been tested?

Yes. The unit has been professionally bench-tested, cleaned, and inspected to verify proper operation before being offered for sale.

Does this ECU replace another part number?

Yes. This ECU supersedes Mercury Part Number 85889129.

Is this a genuine Mercury ECU?

Yes. This is a genuine OEM Mercury Optimax Engine Control Unit.

Does this ECU include a warranty?

Yes. This product includes a 1-Year Warranty, providing added confidence with your purchase.