You are Here:
Tech Library > Mercury and Mercruiser Topics > Mercruiser Serial Numbers
Locating Your Serial Number
Mercruiser product serial numbers in the following format 0W555555 begin with the number 0 and not the letter O. However the site will automatically correct your input if you accidentally enter an O. Serial numbers that do not follow this format but instead have 7 numerical digits are prior to 1980 and cannot be searched on the Parts Finder.
Engines: The serial number tag is located near the STARTER, by the flywheel housing; or, on the ROCKER ARM or FLAME ARRESTOR COVER.
Transom plates: The serial number tag is located on the INNER TRANSOM PLATE inside the boat; or, on the UPPER SWIVEL PIN.
Sterndrives: The serial number tag is located on the UPPER DRIVE SHAFT HOUSING (starboard side or on the back of the housing).

Serial Number Search Tool

Serial Number Search Tool

Serial Number Search Tool
The model of Mercruiser engine can be determined by looking at the last letters of the "engine block code" that is stamped in all complete longblocks by General Motors at the time of assembly. If the serial number, and/or model decals are missing, the engine code will help to determine the engine model. Send an email to sales@perfprotech.com and we will be happy to point you at the location of your particluar engine block code stamping.