Engine age by serial number for Izusu engine (1997?)

[wildernessdave]

I have a 6 digit serial number stamped on the engine block of the 20 hp diesel engine installed in our sailboat. The boat was built in 1997 and it is the original engine, so I am assuming the engine was built around 1997 as well, but I need to find the month and date because we are importing the boat into the US and it is required for importing an engine of that age.

Does anyone know how I can find the age of the engine with the serial number? Internet searches have not turned up anything.

Thanks!

[donradcliffe]

I thought each manufacturer had their own numbering system.