3B2S873010 3B2Q873018 Tohatsu Short Gearbox | Genuine Used Part

🔧 Product Description

Genuine Tohatsu / Nissan M8B-M9.8B 15-Inch Short-Shaft Complete Gearcase - Current Part Number: 3B2Q873018

A genuine short-shaft lower unit for Tohatsu and Nissan 8HP and 9.8HP two-stroke outboards. Original number 3B2S873010 progressed through several revisions to current service number 3B2Q873018. The complete assembly contains the short driveshaft, gear set, propeller shaft, shift components and water-pump section.

⚙️ Key Features

• Genuine Tohatsu complete short-shaft lower unit
• Current number 3B2Q873018
• Original number 3B2S873010
• 15-inch short-shaft configuration
• Used on M8B / M9.8B two-stroke platforms

🚤 Compatibility

• Tohatsu M8B and M8B-series 8HP two-strokes
• Tohatsu M9.8B and M9.8B-series 9.8HP two-strokes
• Nissan Marine NS8B and NS9.8B cross-branded models
• 15-inch short-shaft transom configuration
• Approximate application era: late 1990s onward through continuing service support

🔌 Function

The gearcase transfers power through the pinion and forward or reverse gears, supports the propeller and pumps cooling water to the powerhead.

⚠️ Common Signs of Failure

• Gear oil becomes milky
• Shift engagement is incomplete
• Propeller shaft or driveshaft is bent
• Pinion or bearings become noisy
• Water pump loses prime
• Housing is cracked or skeg is broken

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 3B2S873010 → 3B2S873011 → 3B2S873012 → 3B2S873013 → 3B2S873014 → 3B2Q873018
• The Q-suffix assembly is the current documented service replacement
• Long-shaft M8B / M9.8B lower units use a different driveshaft and complete-unit number

OEM / Related Numbers

• 3B2S873010
• 3B2S873011
• 3B2S873012
• 3B2S873013
• 3B2S873014
• 3B2Q873018
• Nissan Marine NS8B / NS9.8B cross-brand application

Aftermarket / Verified Equivalents

• Parsun, Hidea and other 9.8HP two-stroke clone-platform lower units are functional alternatives only after confirming spline count, shift-rod length and water-tube position
• Aftermarket Tohatsu / Nissan water-pump, seal, bearing and gear kits are available from Sierra and specialist suppliers
• A matching genuine 3B2Q873018 remains the verified complete replacement

📦 Condition

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