8M0236553 Mercury Trim Tab | Genuine Used Part

🔧 Product Description

Genuine Mercury Aluminium Trim Tab Anode - Part Number: 8M0236553

A genuine Mercury aluminium trim tab and sacrificial anode for selected Mercury and Mariner outboards and non-Bravo MerCruiser sterndrives. The shaped tab can be adjusted to counter steering torque while the aluminium body provides sacrificial corrosion protection for the gearcase.

⚙️ Key Features

• Genuine Mercury OEM aluminium trim tab anode
• Current part number 8M0236553
• Supersedes the 31640T and 31640-series references
• Provides steering-torque correction and corrosion protection
• Used on selected 35HP to 125HP outboards and non-Bravo MerCruiser drives

🚤 Compatibility

Commonly used on

• Mercury and Mariner gearcases with an adjustable trim-tab anode
• MerCruiser Alpha-family and earlier non-Bravo sterndrive lower units
• Installations with sufficient propeller clearance for the raised trim-tab profile

Typically suits

• Engine / drive models:
• Mercury / Mariner 35HP
• Mercury / Mariner 40HP
• Mercury / Mariner 45HP
• Mercury / Mariner 50HP
• Mercury / Mariner 55HP
• Mercury / Mariner 60HP
• Mercury / Mariner 65HP
• Mercury / Mariner 70HP
• Mercury / Mariner 75HP
• Mercury / Mariner 80HP
• Mercury / Mariner 90HP
• Mercury / Mariner 100HP
• Mercury / Mariner 115HP
• Mercury / Mariner 125HP
• MerCruiser MC-I, R and MR drives where 31640-series trim tab is specified
• MerCruiser Alpha One
• MerCruiser Alpha One Gen II
• Non-Bravo MerCruiser drives using the matching gearcase tab and bolt pattern
• HP Range: Commonly 35HP - 125HP for outboard applications
• Drive Type: Mercury / Mariner outboard and MerCruiser non-Bravo sterndrive
• Year Range: Approximately 1970s onward, dependent on gearcase and propeller clearance

🔌 Function

The offset fin can be rotated to reduce steering pull caused by propeller torque. The aluminium also corrodes sacrificially in preference to the gearcase, helping protect submerged aluminium components.

⚠️ Common Signs of Failure

• Tab heavily eroded or missing
• Steering pulls strongly to port or starboard
• Corrosion developing on the gearcase
• Tab contacts the propeller
• Mounting bolt seized or loose
• Fin bent, cracked or broken

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 8M0236553 → Supersedes 31640T07
• 31640T07 → Supersedes 31640T5
• 31640T5 → Supersedes 97-31640T5
• 97-31640T5 → Supersedes 316405
• 316405 earlier OEM trim-tab reference

OEM / Related Numbers

• 8M0236553
• 31640T07
• 31640T5
• 97-31640T5
• 316405
• 31640Q4 Quicksilver packaged aluminium trim tab
• 97-822777A2 magnesium freshwater alternative
• 822777A2 magnesium freshwater alternative

Aftermarket / Verified Equivalents

• Quicksilver: 31640Q4 aluminium trim tab anode
• Mercury / Quicksilver: 822777A2 magnesium freshwater alternative
• Marine anode manufacturers: 31640-series aluminium replacement trim tab

📦 Condition

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