0387339 319887 Evinrude Johnson BRP 20" Long Shaft Gearbox | Genuine Used Part

🔧 Product Description

Genuine Johnson Evinrude 50HP-55HP Standard-Shaft Gearcase Assembly - Part Number: 0387339 / Casting Reference 319887

A genuine OMC complete gearcase for selected mid-1970s 50HP and 55HP three-cylinder outboards.

The listing title describes a 20-inch long-shaft unit; however, OEM catalogues identify 0387339 as the standard gearcase assembly and 0387340 as the long-shaft assembly. Number 319887 appears to be a housing or casting reference rather than the complete OEM service number.

⚙️ Key Features

• Genuine OMC complete gearcase assembly
• Correct service number 0387339 / 387339
• Casting reference 319887
• Standard-shaft catalogue configuration
• Mechanical forward-neutral-reverse lower unit
• Used on selected 50HP and 55HP three-cylinder engines

🚤 Compatibility

Documented on selected

• 1975 Evinrude 50HP
• 1975 Johnson 50HP
• 1976 Johnson 55EL76E
• Related 1975-1976 50HP / 55HP three-cylinder gearcase families
• Engine Type: OMC three-cylinder carburetted two-stroke outboard
• Catalogue Configuration: Standard shaft
• Long-Shaft OEM Number: 0387340
• Fitment Requirement: Verify the installed driveshaft length and complete engine model number

🔌 Function

The gearcase contains the driveshaft, bevel gears, clutch dog and propeller shaft, reducing engine speed and providing forward, neutral and reverse.

⚠️ Common Signs of Failure

• Gear oil is milky or contains filings
• Unit jumps out of gear
• Propeller shaft is bent
• Driveshaft splines are worn
• Bearing noise increases with speed
• Housing is cracked or corroded around the bearing carrier

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 0387107 earlier related gearcase
• 0387339 later standard-shaft assembly
• 0388475 related later service assembly
• 0387340 is the corresponding long-shaft gearcase, not the same service number

OEM / Related Numbers

• 0387339
• 387339
• Casting reference 319887
• 0387340 long-shaft assembly
• 0387107 earlier assembly
• 0388475 later related assembly
• 0387326 related water-pump repair kit
• 0389133 related water-pump service kit

Aftermarket / Verified Equivalents

• Specialist rebuilt 0387339 standard-shaft gearcase
• Used complete 50HP / 55HP OMC lower unit
• Sierra and GLM water-pump, seal and bearing components
• No verified new complete aftermarket assembly
• A 20-inch conversion requires the correct OEM long driveshaft and associated housing components rather than relabelling 0387339

📦 Condition

• Genuine used complete gearcase
• Removed from running engine where applicable
• In good working condition unless otherwise stated
• The claimed 20-inch configuration must be physically verified
• Pressure and vacuum testing is recommended