804146 Mercury Tensioner | Genuine Used Part

🔧 Product Description

Genuine Mercury Four-Stroke Timing Belt Tensioner - Part Number: 804146

A genuine used Mercury timing-belt tensioner for selected Yamaha-derived Mercury and Mariner 75HP to 115HP four-stroke outboard motors.

The spring-loaded tensioner maintains the specified tension on the camshaft timing belt, helping keep the crankshaft and camshafts correctly synchronised throughout the engine-speed range.

⚙️ Key Features

• Genuine used Mercury OEM timing-belt tensioner
• Correct part number 804146
• Used with Mercury timing belt 57-804145
• Supports correct camshaft and crankshaft timing
• Suits selected 75HP to 115HP four-stroke engines

🚤 Compatibility

Commonly used on

• Yamaha-derived Mercury and Mariner four-stroke timing-belt systems
• Inline four-cylinder EFI and carburetted four-stroke powerheads

Typically suits

• Engine models:
• Mercury / Mariner 75HP four-stroke - serial 0G960500 to 0T800999
• Mercury / Mariner 75HP four-stroke - serial 0T801000 to 1B226999
• Mercury / Mariner 75HP Bodensee four-stroke - corresponding serial groups
• Mercury 75HP EFI - serial 1B172291 to 1B366822
• Mercury 80HP EFI - serial 1B227000 to 1B366822
• Mercury / Mariner 90HP four-stroke - serial 0G960500 to 0T800999
• Mercury / Mariner 90HP four-stroke - serial 0T801000 to 1B226999
• Mercury 90HP EFI - serial 1B172291 to 1B366822
• Mercury 100HP EFI - serial 1B227000 to 1B366822
• Mercury 115HP EFI - serial 0T178500 to 0T800999
• Mercury 115HP EFI - serial 0T801000 to 1B226999
• Mercury 115HP EFI - serial 1B227000 to 1B366822
• HP Range: 75HP - 115HP
• Engine Type: Mercury / Mariner inline four-cylinder four-stroke outboard
• Year Range: Approximately 1999-2006

🔌 Function

The tensioner applies controlled pressure to the timing belt so the camshafts remain synchronised with the crankshaft.

⚠️ Common Signs of Failure

• Timing belt becomes loose or flaps during operation
• Tensioner bearing produces a grinding or rattling noise
• Engine timing becomes unstable
• Belt wears unevenly or moves off-centre
• Tensioner arm is seized or spring pressure is weak
• Engine suffers severe internal damage after belt disengagement

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 804146 current original OEM tensioner reference

OEM / Related Numbers

• 804146
• 804146T
• 57-804145 related timing belt
• 804147 related tensioner spring
• 804143 related mounting bolt
• 804149 related valve plate
• 804150 related bolt
• 804153 related key
• 745061272552

Aftermarket / Verified Equivalents

• No aftermarket equivalent

📦 Condition

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