I doubt the engine# will help, like you i also think you'd be in with a good chance that one from another engine will fit, you could do with a part#
what year is it, post the vin# if you dont know
I have a hunch it will be the same as the YB 100
heres one
http://www.ebay.co.uk/itm/GenuineYamaha-2N3-16341-00-A794-/260841086266