Where is my Mercury / MerCruiser Serial Number?
Locate your serial number using our visual guide below, then use our parts lookup tool to find the exact diagrams for your engine.
Go to Parts Lookup Tool →Is it a Serial Number?
Make sure you aren't looking at a casting number. Standard Mercury serial numbers follow this format:
Examples: 0M123456 or 3A123456. Older serial numbers will not have the first digit or the first letter.
1. Mercury Outboard Engines
On modern Mercury Outboards, the serial number tag is located on the transom bracket (either the starboard or port side). Some models also have it on the top of the engine block.
- Look near the swivel bracket toggle mechanism.
- The tag also features the manufacturing year and model description.
2. MerCruiser Sterndrive & Inboard Engines
For MerCruiser gas and diesel engines, placement depends on the production era:
Newer Models (Late 1990s - Present)
Look for a large sticker located right on top of the engine plastic cover or the flame arrestor cover.
Older Models
Look for a stamped metal plate riveted to the engine block near the starter motor, flywheel housing, or alternative valve cover edges.
3. Alpha & Bravo Drive Units & Transoms
Your drive unit serial number is independent of the engine serial number. It can be found directly on the upper driveshaft housing.
Drive Unit: Look for a decal on the port or starboard side of the upper driveshaft housing. On newer Bravos it is usually stamped in the upper housing behind the rear cover (partial disassembly required).
Many times it's stamped underneath the Mercruiser logo on the top side of the housing.
- Transom Assembly: Located on an identification tag on the inner transom plate inside the boat, or the outer transom assembly.