821306a6 821306t6 Mercury gearbox 13x26 2.00:1 | Genuine Used Part

🔧 Product Description

Genuine Mercury 30HP / 40HP Two-Stroke 20-Inch Gearcase - Part Numbers: 821306A6 / 821306T6

A genuine used Mercury complete lower unit for 30HP and 40HP two-cylinder two-stroke outboards. The black 20-inch assembly uses a 13-tooth pinion and 26-tooth forward gear, producing a 2.00:1 reduction ratio. Mercury 821306T6 is the later service number for 821306A6.

⚙️ Key Features

• Genuine Mercury Marine complete gearcase
• Current part number 1682-821306T6
• Earlier reference 821306A6
• 20-inch long shaft with 2.00:1 ratio
• 13-tooth pinion and 26-tooth forward gear

🚤 Compatibility

Commonly used on

• Mercury and Mariner 30HP two-cylinder two-strokes
• Mercury and Mariner 40HP two-cylinder two-strokes
• 20-inch long-shaft standard-rotation applications

Typically suits

• Commonly found on engines from the 1980s through early 2000s
• Example applications include mid-1990s and late-1990s Mercury 30HP / 40HP two-strokes
• Not the later three-cylinder 40HP / 50HP gearcase family
• Confirm engine serial and two-cylinder powerhead before installation
• HP Range: 30HP - 40HP
• Shaft Length: 20 inches / L
• Gear Ratio: 2.00:1
• Gear Teeth: 13 pinion / 26 forward
• Engine Type: Mercury / Mariner two-cylinder two-stroke

🔌 Function

The gearcase converts driveshaft rotation into propeller rotation, provides forward-neutral-reverse operation and pumps cooling water to the powerhead.

⚠️ Common Signs of Failure

• Water or metal particles in the lubricant
• Clutch dog slips under load
• Bearing rumble
• Bent propeller shaft
• Cracked case or damaged skeg

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 821306T6 is the later service reference for 821306A6
• 821306A6 is the earlier assembly number
• Related 821306T8 is the short-shaft version and is not interchangeable

OEM / Related Numbers

• 1682-821306T6
• 821306T6
• 821306A6
• 821306A16 and 821306A35 related production revisions
• 821306T8 short-shaft related assembly
• 26-series gearcase seal kit and water-pump parts vary by serial

Aftermarket / Verified Equivalents

• BoatEngine professionally remanufactured 821306T6 lower unit
• Remanufactured Mercury 30HP / 40HP two-cylinder 2.00:1 gearcases
• Aftermarket seal, bearing and water-pump kits
• Sierra and Mallory replacement impellers and gearcase seals
• Used genuine 821306-series assemblies after ratio and shaft verification

📦 Condition

• Genuine used part
• Removed from running engine or vessel where applicable
• In good working condition unless otherwise stated