# 858723T1 Mercury Harness | Genuine Used Part

🔧 Product Description

  

Genuine Mercury Harness Assembly - Part Number: 84-858723T1

  

A genuine Mercury harness assembly used on selected Mercury 75HP to 115HP four-stroke and EFI four-stroke outboards. This harness must be matched by exact serial range and connector layout before installation.

  

⚙️ Key Features

  

• Genuine Mercury harness assembly

• Correct OEM part number 84-858723T1

• Used on Mercury 75HP to 115HP four-stroke outboards

• Supports EFI and non-EFI four-stroke electrical layouts

• Must be matched by serial-numbered parts diagram

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 84-858723T1 current Mercury harness reference

  

OEM / Related Numbers:

  

• 858723T1

• 84-858723T1

• 858723-T1

• Harness assembly

• UPC: 745061443099

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• Mercury 75HP / 90HP four-stroke outboards

• Mercury 75 EFI / 80 EFI / 90 EFI / 100 EFI / 115 EFI four-stroke outboards

  

Typically suits:

  

• Mercury 75HP 4-Stroke - serial 0G960500 to 0T800999

• Mercury 75HP 4-Stroke - serial 0T801000 to 1B226999

• Mercury 75HP 4-Stroke Bodensee - serial 0G960500 to 0T800999

• Mercury 75HP 4-Stroke Bodensee - serial 0T801000 to 1B226999

• Mercury 75 EFI 4-Stroke - serial 1B172291 to 1B366822

• Mercury 80 EFI 4-Stroke - serial 1B227000 to 1B366822

• Mercury 90HP 4-Stroke - serial 0G960500 to 0T800999

• Mercury 90HP 4-Stroke - serial 0T801000 to 1B226999

• Mercury 90 EFI 4-Stroke - serial 1B172291 to 1B366822

• Mercury 100 EFI 4-Stroke - serial 1B227000 to 1B366822

• Mercury 115 EFI 4-Stroke - serial 0T178500 to 0T800999

• Mercury 115 EFI 4-Stroke - serial 0T801000 to 1B226999

• Mercury 115 EFI 4-Stroke - serial 1B227000 to 1B366822

• HP Range: 75HP / 80HP / 90HP / 100HP / 115HP

• Engine Type: Mercury four-stroke and EFI four-stroke outboard

• Year Range: Serial-number controlled

• Serial Note: Confirm serial number and harness plug layout before installation.

  

🔌 Function

  

The harness assembly carries engine electrical power and signal circuits between sensors, control components, relays and engine wiring junctions.

  

Common signs of failure:

  

• Intermittent no-start or cut-out

• EFI or sensor faults caused by damaged wiring

• Corroded plug terminals

• Broken locking tabs

• Warning horn or gauge faults

• Fault changes when harness is moved

• Damaged insulation or previous repair joins

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 12.5 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Electronic Components | ECU CDI & Electrical Parts

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 12.50 AUD | In stock |

## Images

- 858723T1 Mercury Harness | Genuine Used Part
- 858723T1 Mercury Harness | Genuine Used Part
- 858723T1 Mercury Harness | Genuine Used Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/858723t1-mercury-harness-genuine-used-part)
> Updated: 2026-06-29