0305123 Evinrude Johnson O-Ring | Genuine OEM BRP Outboard Part

🔧 Product Description

Genuine BRP Crankcase Head and Bearing Carrier O-Ring - Part Number: 0305123

A genuine BRP large-diameter O-ring used to seal the crankcase head or propeller-shaft bearing carrier on selected Evinrude, Johnson and OMC outboards and sterndrives.

The O-ring has an approximate inside diameter of 3.780 inches and a cross-section of 0.135 inches. It prevents oil, gear lubricant or water passing around the outer diameter of the installed housing.

⚙️ Key Features

• Genuine BRP OEM large-diameter O-ring
• Correct OMC part number 0305123
• Used on crankcase-head and bearing-carrier assemblies
• Approximate 3.780-inch inside diameter
• Cross-references with Sierra, GLM, Mallory and SEI numbers

🚤 Compatibility

Commonly used on

• Evinrude and Johnson propeller-shaft bearing carriers
• Evinrude and Johnson crankcase-head assemblies
• OMC outboard and sterndrive housing applications using the 3.780-inch O-ring

Typically suits

• Engine models:
• Evinrude / Johnson 65HP outboards
• Evinrude / Johnson 70HP outboards
• Evinrude / Johnson 75HP outboards
• Evinrude / Johnson 85HP V4 outboards
• Evinrude / Johnson 90HP V4 outboards
• Evinrude / Johnson 100HP outboards
• Evinrude / Johnson 115HP V4 outboards
• Evinrude / Johnson 120HP V4 outboards
• Evinrude / Johnson 125HP outboards
• Evinrude / Johnson 135HP V4 and V6 outboards
• Evinrude / Johnson 140HP V4 outboards
• Evinrude / Johnson 150HP V6 outboards
• Evinrude / Johnson 175HP V6 outboards
• Evinrude / Johnson 200HP V6 outboards
• Evinrude / Johnson 225HP V6 outboards
• Evinrude / Johnson 235HP V6 outboards
• OMC sterndrive bearing-carrier or crankcase-head applications specifying 0305123
• HP Range: Approximately 65HP - 235HP
• Engine Type: Evinrude / Johnson V4 and V6 outboard; selected OMC sterndrive
• Year Range: Approximately 1968 - 2006

🔌 Function

The O-ring seals the outside of the crankcase head or bearing carrier against its housing. In a gearcase it retains lubricant and prevents water entry; in a powerhead it prevents oil or crankcase leakage.

⚠️ Common Signs of Failure

• Gear lubricant leaking around the bearing carrier
• Milky or water-contaminated gear oil
• Gearcase fails pressure or vacuum testing
• Oil seepage around the crankcase head
• O-ring flattened, pinched, hardened or cut
• Corrosion beneath the bearing-carrier sealing surface

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 0305123 current OEM service reference
• 0321119 related / interchangeable OMC reference
• 0777380 related BRP service-pack reference

OEM / Related Numbers

• 0305123
• 305123
• 0321119
• 321119
• 0777380
• 777380

Aftermarket / Verified Equivalents

• Sierra: 18-7133
• Sierra: 18-7133-9
• GLM: 82400
• Mallory: 9-76529
• SEI Marine: 95-306-04

📦 Condition

• Genuine BRP part
• Brand new
• Supplied in original or equivalent packaging