258M142860 Mercury MerCruiser O-Ring | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Shift Shaft Bushing O-Ring - Part Number: 25-8M0142860

A genuine Quicksilver O-ring used with the shift shaft bushing service family on modern Mercury V6 and V8 FourStroke gear housings. This O-ring is used in the gear housing / shift shaft bushing area on 3.4L V6 and 4.6L V8 models where the parts diagram specifies 25-8M0142860.

⚙️ Key Features

• Genuine Quicksilver OEM O-ring

• Correct Mercury part number 25-8M0142860

• Used with modern Mercury gear housing shift shaft bushing assemblies

• Related to Design 1 shift shaft bushing 23-8M0142859

• Fits V6 and V8 FourStroke gearcase service applications where specified

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 25-8M0142860 current OEM O-ring reference

OEM / Related Numbers:

• 25-8M0142860

• 8M0142860

• 258M142860

• Mercury 25-8M0142860

• Quicksilver 25-8M0142860

• Shift shaft bushing O-ring

• Gear housing O-ring

• 23-8M0142859 related Design 1 shift shaft bushing

Aftermarket / Verified Equivalents:

• No aftermarket equivalent

🚤 Compatibility

Commonly used on:

• Mercury 3.4L V6 FourStroke gear housing shift shaft assemblies

• Mercury 4.6L V8 FourStroke gear housing shift shaft assemblies

• Mercury Pro XS and SeaPro gearcases using the Design 1 shift shaft bushing service family

• Gear housing reseal work where 25-8M0142860 is specified

Typically suits:

• Engine models:

• Mercury 175HP 3.4L V6 FourStroke - serial 2B529482 and up, 4.80 torpedo gear housing

• Mercury 175HP 3.4L V6 FourStroke - serial 2B529482 and up, 5.44 torpedo gear housing

• Mercury 175HP 3.4L V6 Pro XS FourStroke - serial 2B529482 and up

• Mercury 200HP 3.4L V6 FourStroke - serial 2B529482 and up, 4.80 torpedo gear housing

• Mercury 200HP 3.4L V6 FourStroke - serial 2B529482 and up, 5.44 torpedo gear housing

• Mercury 200HP 3.4L V6 SeaPro FourStroke - serial 2B529482 and up

• Mercury 200HP 4.6L V8 Pro XS FourStroke - serial 2B529482 and up, 4.80 torpedo gear housing

• Mercury 200HP 4.6L V8 Pro XS FourStroke - serial 2B529482 and up, 5.44 torpedo gear housing

• Mercury 200HP 4.6L V8 Pro XS FourStroke - serial 2B529482 and up, Torque Master gear housing

• Mercury 225HP 3.4L V6 FourStroke - serial 2B529482 and up

• Mercury 225HP 4.6L V8 SeaPro FourStroke - serial 2B529482 and up

• Mercury 225HP 4.6L V8 Pro XS FourStroke - serial 2B529482 and up

• Mercury 250HP 4.6L V8 FourStroke - serial 2B529482 and up

• Mercury 250HP 4.6L V8 Pro XS FourStroke - serial 2B529482 and up

• Mercury 300HP 4.6L V8 FourStroke - serial 2B529482 and up

• Mercury 300HP 4.6L V8 Pro XS FourStroke - serial 2B529482 and up

• HP Range: commonly 175HP - 300HP where specified

• Engine Type: Mercury 3.4L V6 and 4.6L V8 FourStroke outboard

• System Type: Gear housing / shift shaft bushing O-ring

• Gearcase Types: 4.80 torpedo, 5.44 torpedo and Torque Master where specified

🔌 Function

The O-ring seals the shift shaft bushing area to help prevent water entry and lubricant leakage around the gear housing shift shaft service point.

Common signs of failure:

• Water intrusion around shift shaft area

• Gearcase pressure or vacuum test failure

• O-ring cut, flattened or missing during bushing service

• Corrosion around shift shaft bore

• Gear oil seepage near shift shaft bushing

• Replacement required during shift shaft bushing service

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging