The serial number tag is found to the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Situated in between the thumb screws above the steering tube. The good news is, PartsVu contains a wealth of resources to assist you to find the Mercury outboard parts you need to https://eduardomzdlr.alltdesign.com/the-basic-principles-of-marine-outboards-for-sale-55764246